[eslint config] [base] [new] update base ecmaVersion to 2018; remove deprecated experimentalObjectRestSpread option

Author: ljharb

packages/eslint-config-airbnb-base/index.js

@@ -9,11 +9,8 @@ module.exports = {
     './rules/imports',
   ].map(require.resolve),
   parserOptions: {
-    ecmaVersion: 2017,
+    ecmaVersion: 2018,
     sourceType: 'module',
-    ecmaFeatures: {
-      experimentalObjectRestSpread: true,
-    },
   },
   rules: {
     strict: 'error',