feat!: update mocha to v8 (#6121)

Author: haoqunjiang

docs/migrations/migrate-from-v4.md

@@ -114,7 +114,7 @@ Please consider switching to ESLint. You can check out [`tslint-to-eslint-config
 
 ### Unit-Mocha Plugin
 
-* `mocha` is upgraded from v6 to v7, please refer to the [release notes of mocha v7](https://github.com/mochajs/mocha/releases/tag/v7.0.0) for a complete list of breaking changes.
+* `mocha` is upgraded from v6 to v8, please refer to the release notes of [mocha v7](https://github.com/mochajs/mocha/releases/tag/v7.0.0) and [mocha v8](https://github.com/mochajs/mocha/releases/tag/v8.0.0) for a complete list of breaking changes.
 * `jsdom` is upgraded from v15 to v16, the breaking changes are listed at [`jsdom` v16.0.0 release](https://github.com/jsdom/jsdom/releases/tag/16.0.0)
 
 ### Internal Packages

packages/@vue/cli-plugin-e2e-webdriverio/generator/index.js

@@ -3,7 +3,7 @@ const { installedBrowsers } = require('@vue/cli-shared-utils')
 const applyTS = module.exports.applyTS = (api, invoking) => {
   api.extendPackage({
     devDependencies: {
-      '@types/mocha': '^8.0.1'
+      '@types/mocha': require('../package.json').dependencies['@types/mocha']
     }
   })
 

packages/@vue/cli-plugin-e2e-webdriverio/package.json

@@ -25,7 +25,7 @@
     "access": "public"
   },
   "dependencies": {
-    "@types/mocha": "^8.0.1",
+    "@types/mocha": "^8.0.4",
     "@vue/cli-shared-utils": "^4.5.8",
     "@wdio/cli": "^6.10.5",
     "@wdio/local-runner": "^6.10.5",

packages/@vue/cli-plugin-typescript/package.json

@@ -47,7 +47,7 @@
   "devDependencies": {
     "@types/chai": "^4.2.11",
     "@types/jest": "^26.0.17",
-    "@types/mocha": "^7.0.2",
+    "@types/mocha": "^8.0.4",
     "jscodeshift": "^0.11.0",
     "typescript": "~3.9.3",
     "vue-class-component": "^7.2.3",

packages/@vue/cli-plugin-unit-mocha/generator/index.js

@@ -62,7 +62,7 @@ const applyESLint = module.exports.applyESLint = api => {
 const applyTS = module.exports.applyTS = (api, invoking) => {
   api.extendPackage({
     devDependencies: {
-      '@types/mocha': '^7.0.2',
+      '@types/mocha': '^8.0.4',
       '@types/chai': '^4.2.11'
     }
   })

packages/@vue/cli-plugin-unit-mocha/package.json

@@ -25,7 +25,7 @@
     "@vue/cli-shared-utils": "^4.5.8",
     "jsdom": "^16.4.0",
     "jsdom-global": "^3.0.2",
-    "mocha": "^7.2.0",
+    "mocha": "^8.2.1",
     "mochapack": "^2.0.2"
   },
   "devDependencies": {