Bump eslint from 4.19.1 to 6.5.1 (#1948)

* Bump eslint from 4.19.1 to 6.5.1

Bumps [eslint](https://github.com/eslint/eslint) from 4.19.1 to 6.5.1.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v4.19.1...v6.5.1)

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

* better ignore rules for eslint

* set ecmascript version to support object spread operator

.eslintrc

@@ -54,5 +54,8 @@
 
     "promise/always-return": "off",
     "promise/avoid-new": "off",
+  },
+  "parserOptions": {
+    "ecmaVersion": 2018
   }
 }

package.json

@@ -17,8 +17,8 @@
     "prepare-docs": "scripts/prepare-docs.sh",
     "lint": "npm run lint:js && npm run lint:sol",
     "lint:fix": "npm run lint:js:fix",
-    "lint:js": "eslint .",
-    "lint:js:fix": "eslint . --fix",
+    "lint:js": "eslint --ignore-path .gitignore .",
+    "lint:js:fix": "eslint --ignore-path .gitignore . --fix",
     "lint:sol": "solhint --max-warnings 0 \"contracts/**/*.sol\"",
     "prepare": "node scripts/prepare.js",
     "release": "scripts/release/release.sh",
@@ -49,7 +49,7 @@
     "@openzeppelin/test-helpers": "^0.5.1",
     "chai": "^4.2.0",
     "concurrently": "^5.0.0",
-    "eslint": "^4.19.1",
+    "eslint": "^6.5.1",
     "eslint-config-standard": "^11.0.0",
     "eslint-plugin-import": "^2.18.2",
     "eslint-plugin-mocha-no-only": "^1.1.0",