chore(deps): upgrade eslint and eslint-config-prettier (#2130)

Author: hiroppy

.eslintrc

@@ -5,7 +5,8 @@
     "window": true
   },
   "parserOptions": {
-    "sourceType": "script"
+    "sourceType": "script",
+    "ecmaVersion": 10
   },
   "rules": {
     "curly": "error",

examples/cli/history-api-fallback/app.js

@@ -1,7 +1,5 @@
 'use strict';
 
-/* global XMLHttpRequest */
-
 const path = document.location.pathname;
 const target = document.querySelector('#target');
 const style = document.createElement('style');

package-lock.json

@@ -82,8 +82,8 @@
     "commitlint-azure-pipelines-cli": "^1.0.2",
     "copy-webpack-plugin": "^5.0.3",
     "css-loader": "^2.1.1",
-    "eslint": "^5.16.0",
-    "eslint-config-prettier": "^5.1.0",
+    "eslint": "^6.0.1",
+    "eslint-config-prettier": "^6.0.0",
     "eslint-config-webpack": "^1.2.5",
     "eslint-plugin-import": "^2.18.0",
     "execa": "^1.0.0",