* Fix link to GSN overview

* Update contracts/GSN/README.adoc

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

* issue#1980

* fix public to external

Bumps [eslint-plugin-import](https://github.com/benmosher/eslint-plugin-import) from 2.18.2 to 2.20.0.
- [Release notes](https://github.com/benmosher/eslint-plugin-import/releases)
- [Changelog](https://github.com/benmosher/eslint-plugin-import/blob/master/CHANGELOG.md)
- [Commits](https://github.com/benmosher/eslint-plugin-import/compare/v2.18.2...v2.20.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [@openzeppelin/gsn-helpers](https://github.com/OpenZeppelin/openzeppelin-gsn-helpers) from 0.2.1 to 0.2.3.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-gsn-helpers/releases)
- [Commits](https://github.com/OpenZeppelin/openzeppelin-gsn-helpers/compare/v0.2.1...v0.2.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [openzeppelin-docs-utils](https://github.com/OpenZeppelin/docs-utils) from `dc7ce30` to `f6b5291`.
- [Release notes](https://github.com/OpenZeppelin/docs-utils/releases)
- [Commits](https://github.com/OpenZeppelin/docs-utils/compare/dc7ce3006b6065cc4edebe53896644da5bd7dbec...f6b5291a2e289186376c23d08598cf9e99ed39b4)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

* Reorder navbar

* Adapt content to new docsite structure, add links

* Fix list

* fix list

* Apply suggestions from code review

Co-Authored-By: Francisco Giordano <frangio.1@gmail.com>

* Update index.adoc

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

Bumps [mocha](https://github.com/mochajs/mocha) from 6.2.2 to 7.0.0.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mochajs/mocha/compare/v6.2.2...v7.0.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [handlebars](https://github.com/wycats/handlebars.js) from 4.1.2 to 4.5.3. **This update includes a security fix.**
- [Release notes](https://github.com/wycats/handlebars.js/releases)
- [Changelog](https://github.com/wycats/handlebars.js/blob/master/release-notes.md)
- [Commits](https://github.com/wycats/handlebars.js/compare/v4.1.2...v4.5.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Code sample for MyCrowdsaleDeployer causes TypeError:
```
browser/MyCrowdsaleDeployer.sol:21:13: TypeError: Invalid type for argument in function call. 
Invalid implicit conversion from address to contract IERC20 requested.
            address(token)            // the token
            ^------------^
```
Change: 
```solidity
address(token)   // the token
```
To:
```solidity
token   // the token
```

Reported by community member in the forum: https://forum.openzeppelin.com/t/invalid-implicit-conversion-from-address-to-contract-ierc20-requested/1937

* Correct documentation for isContract check

* Update Address.sol

* Update Address.sol

* add missing newline before asciidoc list

Bumps [eslint-utils](https://github.com/mysticatea/eslint-utils) from 1.4.0 to 1.4.3. **This update includes security fixes.**
- [Release notes](https://github.com/mysticatea/eslint-utils/releases)
- [Commits](https://github.com/mysticatea/eslint-utils/compare/v1.4.0...v1.4.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [openzeppelin-docs-utils](https://github.com/OpenZeppelin/docs-utils) from `8e3fa25` to `dc7ce30`.
- [Release notes](https://github.com/OpenZeppelin/docs-utils/releases)
- [Commits](https://github.com/OpenZeppelin/docs-utils/compare/8e3fa255734046186a0cd4c530cca6213629be36...dc7ce3006b6065cc4edebe53896644da5bd7dbec)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

* migrate to openzeppelin-docs-preview script

* update netlify configuration

* update docs-preview-script dependency

* remove old docs directory from gitignore

* update oz-docs script for live reload

* update oz-docs scripts to latest

* replace child_process.execFileSync with spawnSync

* update oz-docs-preview

Bumps [eslint-utils](https://github.com/mysticatea/eslint-utils) from 1.4.0 to 1.4.3. **This update includes security fixes.**
- [Release notes](https://github.com/mysticatea/eslint-utils/releases)
- [Commits](https://github.com/mysticatea/eslint-utils/compare/v1.4.0...v1.4.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

* Sketch

* Migrate all tests to test-env

* Finish migration to test-env

* Add config

* Work on GSN tests

* Migrate to newer test-env version and loader syntax

* Add GSN setup

* Finish test-env migration

* Setup coverage using test-env

* Migrate to npm package

* Fix package.json

* Add compile step to CI

* Add comment on coverage setup

* Remove dependency on @truffle/contract

* Fix package-lock merge

* Fix linter errors

* Upgrade test-environment, depend locally on ganche-coverage

* Improve coverage script

* Improve sign.js API

* Move accounts destructuring to describe block

* Switch to prebuilt ethereumjs-vm package

* Upgrade test-enviroment version

* use workspace in circleci config

* remove unnecessary npx

* Changes ERC777 external functions to public for allowing overrides #1994

* Changes ERC777 external functions to public for allowing overrides (#1994)

Bumps [nodemon](https://github.com/remy/nodemon) from 1.19.4 to 2.0.1.
- [Release notes](https://github.com/remy/nodemon/releases)
- [Commits](https://github.com/remy/nodemon/compare/v1.19.4...v2.0.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

* Improve gas efficiency of reentrancyGuard

* Add changelog entry

* Fix ReentrancyGuard test

Bumps [@openzeppelin/test-helpers](https://github.com/OpenZeppelin/openzeppelin-test-helpers) from 0.5.3 to 0.5.4.
- [Release notes](https://github.com/OpenZeppelin/openzeppelin-test-helpers/releases)
- [Changelog](https://github.com/OpenZeppelin/openzeppelin-test-helpers/blob/master/CHANGELOG.md)
- [Commits](https://github.com/OpenZeppelin/openzeppelin-test-helpers/compare/v0.5.3...v0.5.4)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

* Bump solidity-docgen from 0.3.11 to 0.3.13

Bumps solidity-docgen from 0.3.11 to 0.3.13.

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

* fix broken crossreference links

* feat: add baseTokenURI

* fix: tests

* chore: dev notation

* chore: changelog

* chore: typo

* Remove extra getters, return empty URI by default

* Update docs

* Rename baseTokenURI to baseURI

* Roll back visibility change of tokenURI

* Update changelog entry

* Version setBaseURI docs

* Improve internal names and comments

* Fix compilation errors

* Add an external getter for baseURI

* Update ReentrancyGuard for Istanbul Hard Fork

Changes:
Added L37, `_guardCounter = 1;`

Rationale:
The planned _Istanbul Hard Fork_ will implement [EIP 2200](https://github.com/ethereum/EIPs/blob/e4d4ea348e06c54d0075c400dc7b72430d427ff1/EIPS/eip-2200.md), which implements "net gas metering" for `sstore` operations. If the final value of `_guardCounter` is unchanged relative to the original value of it, a gas refund will be applied and charges for changing the value of `_guardCounter` will effectively not exist. This ends up being cheaper than the current implementation ONLY AFTER Istanbul. Before Istanbul, the added line actually ends up costing more gas.

Note that if `_guardCounter` is `0` initially, the initial cost and subsequent refund will both be larger than if `_guardCounter` is `1` initially. Although in both cases, the net gas cost (`gasCost - gasRefund`) are equal, it's better in terms of cost to have both the gas cost and refund smaller, as there is some limit to the percentage of a gas refund that can actually be realized.

* Update CHANGELOG.md

Added note for change to ReentrancyGuard.sol

* Update ReentrancyGuard.sol

* Update CHANGELOG.md

Bumps [ethereumjs-util](https://github.com/ethereumjs/ethereumjs-util) from 6.1.0 to 6.2.0.
- [Release notes](https://github.com/ethereumjs/ethereumjs-util/releases)
- [Changelog](https://github.com/ethereumjs/ethereumjs-util/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ethereumjs/ethereumjs-util/compare/v6.1.0...v6.2.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps solidity-docgen from 0.3.9 to 0.3.11.

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Bumps [truffle](https://github.com/trufflesuite/truffle) from 5.0.42 to 5.0.44.
- [Release notes](https://github.com/trufflesuite/truffle/releases)
- [Commits](https://github.com/trufflesuite/truffle/compare/truffle@5.0.42...truffle@5.0.44)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

"standard also bring" -> "standard also brings"
"killer feature are" -> "killer feature is"