Bump ESLint to v8 and related plugins (#675)

Author: SergeAstapov

.eslintrc.js

@@ -2,12 +2,13 @@
 
 module.exports = {
   root: true,
-  parser: 'babel-eslint',
+  parser: '@babel/eslint-parser',
   parserOptions: {
-    ecmaVersion: 2018,
+    ecmaVersion: 'latest',
     sourceType: 'module',
-    ecmaFeatures: {
-      legacyDecorators: true,
+    requireConfigFile: false,
+    babelOptions: {
+      plugins: [['@babel/plugin-proposal-decorators', { decoratorsBeforeExport: true }]],
     },
   },
   plugins: ['ember'],
@@ -24,6 +25,7 @@ module.exports = {
       files: [
         './.eslintrc.js',
         './.prettierrc.js',
+        './.stylelintrc.js',
         './.template-lintrc.js',
         './ember-cli-build.js',
         './index.js',
@@ -39,11 +41,10 @@ module.exports = {
         browser: false,
         node: true,
       },
-      plugins: ['node'],
-      extends: ['plugin:node/recommended'],
+      extends: ['plugin:n/recommended'],
     },
     {
-      // Test files:
+      // test files
       files: ['tests/**/*-test.{js,ts}'],
       extends: ['plugin:qunit/recommended'],
     },