Fix eslint and eslint-plugin-github dependency conflicts

.eslintignore

+node_modules
+dist/**

.eslintrc.json

 {
   "parserOptions": {
+    "ecmaVersion": 2015,
     "sourceType": "module"
   },
   "globals": {

package.json

@@ -9,8 +9,8 @@
   "devDependencies": {
     "abortcontroller-polyfill": "^1.1.9",
     "chai": "^4.1.2",
-    "eslint": "^4.19.1",
-    "eslint-plugin-github": "^1.6.0",
+    "eslint": "^7.20.0",
+    "eslint-plugin-github": "^4.1.1",
     "karma": "^3.0.0",
     "karma-chai": "^0.1.0",
     "karma-chrome-launcher": "^2.2.0",