Migrate to Hardhat (#2397)

package.json

@@ -10,7 +10,7 @@
     "/test/behaviors"
   ],
   "scripts": {
-    "compile": "scripts/compile.sh",
+    "compile": "buidler compile",
     "coverage": "scripts/coverage.sh",
     "docs": "oz-docs",
     "docs:watch": "npm run docs watch contracts 'docs/*.hbs'",
@@ -20,12 +20,12 @@
     "lint:js": "eslint --ignore-path .gitignore .",
     "lint:js:fix": "eslint --ignore-path .gitignore . --fix",
     "lint:sol": "solhint --max-warnings 0 \"contracts/**/*.sol\"",
-    "prepublish": "rimraf build contracts/build",
+    "prepublish": "rimraf build contracts/build artifacts",
     "prepare": "npm run compile",
-    "prepack": "node scripts/remove-ignored-artifacts.js",
+    "prepack": "scripts/prepack.sh",
     "release": "scripts/release/release.sh",
     "version": "scripts/release/version.sh",
-    "test": "mocha --exit --recursive"
+    "test": "buidler test"
   },
   "repository": {
     "type": "git",
@@ -46,12 +46,13 @@
   },
   "homepage": "https://openzeppelin.com/contracts/",
   "devDependencies": {
-    "@openzeppelin/cli": "^2.8.2",
+    "@nomiclabs/buidler": "^1.4.8",
+    "@nomiclabs/buidler-truffle5": "^1.3.4",
+    "@nomiclabs/buidler-web3": "^1.3.4",
     "@openzeppelin/docs-utils": "^0.1.0",
     "@openzeppelin/gsn-helpers": "^0.2.3",
     "@openzeppelin/gsn-provider": "^0.1.10",
-    "@openzeppelin/test-environment": "^0.1.4",
-    "@openzeppelin/test-helpers": "^0.5.6",
+    "@openzeppelin/test-helpers": "^0.5.9",
     "chai": "^4.2.0",
     "eslint": "^6.5.1",
     "eslint-config-standard": "^14.1.1",
@@ -67,8 +68,8 @@
     "micromatch": "^4.0.2",
     "mocha": "^8.0.1",
     "rimraf": "^3.0.2",
-    "solhint": "^3.0.0",
-    "solidity-coverage": "github:rotcivegaf/solidity-coverage#5875f5b7bc74d447f3312c9c0e9fc7814b482477",
+    "solhint": "^3.2.0",
+    "solidity-coverage": "^0.7.11",
     "solidity-docgen": "^0.5.3"
   },
   "dependencies": {}