restore openzeppelin-contracts-ethereum-package files

.gitignore

@@ -50,3 +50,5 @@ contracts/README.md
 
 # temporary artifact from solidity-coverage
 allFiredEvents
+
+.openzeppelin/.session

.openzeppelin/project.json

+{
+  "manifestVersion": "2.2",
+  "name": "@openzeppelin/contracts-ethereum-package",
+  "publish": true,
+  "version": "3.0.0",
+  "contracts": {
+    "ERC20PresetMinterPauserUpgradeSafe": "ERC20PresetMinterPauserUpgradeSafe",
+    "ERC721PresetMinterPauserAutoIdUpgradeSafe": "ERC721PresetMinterPauserAutoIdUpgradeSafe"
+  },
+  "dependencies": {},
+  "compiler": {
+    "manager": "openzeppelin",
+    "compilerSettings": {
+      "optimizer": {
+        "enabled": true,
+        "runs": "200"
+      }
+    },
+    "solcVersion": "0.6.7",
+    "artifactsDir": "build/contracts",
+    "contractsDir": "contracts",
+    "typechain": {
+      "enabled": false
+    }
+  },
+  "telemetryOptIn": false
+}

contracts/package.json

-{
-  "name": "@openzeppelin/contracts",
-  "version": "3.1.0",
-  "description": "Secure Smart Contract library for Solidity",
-  "files": [
-    "**/*.sol",
-    "/build/contracts/*.json",
-    "!/mocks",
-    "!/examples"
-  ],
-  "scripts": {
-    "prepare": "bash ../scripts/prepare-contracts-package.sh",
-    "prepare-docs": "cd ..; npm run prepare-docs"
-  },
-  "repository": {
-    "type": "git",
-    "url": "https://github.com/OpenZeppelin/openzeppelin-contracts.git"
-  },
-  "keywords": [
-    "solidity",
-    "ethereum",
-    "smart",
-    "contracts",
-    "security",
-    "zeppelin"
-  ],
-  "author": "OpenZeppelin Community <maintainers@openzeppelin.org>",
-  "license": "MIT",
-  "bugs": {
-    "url": "https://github.com/OpenZeppelin/openzeppelin-contracts/issues"
-  },
-  "homepage": "https://openzeppelin.com/contracts/"
-}