Fix: fixed #1

vuejs/vue-jest#403 (comment)

For Vue2:
```
npm install --save-dev @vue/cli-plugin-unit-jest@next @vue/vue2-jest jest
```

For Vue3：
```
npm install --save-dev @vue/cli-plugin-unit-jest@next @vue/vue3-jest jest ts-jest
```

Author: snowdream

Diff for: jest.config.js

@@ -1,7 +1,7 @@
 module.exports = {
   moduleFileExtensions: ['js', 'jsx', 'json', 'vue'],
   transform: {
-    '^.+\\.vue$': 'vue-jest',
+    '^.+\\.vue$': '@vue/vue2-jest',
     '.+\\.(css|styl|less|sass|scss|svg|png|jpg|ttf|woff|woff2)$':
       'jest-transform-stub',
     '^.+\\.jsx?$': 'babel-jest'

Diff for: package.json

@@ -48,9 +48,10 @@
   "devDependencies": {
     "@vue/cli-plugin-babel": "4.4.4",
     "@vue/cli-plugin-eslint": "4.4.4",
-    "@vue/cli-plugin-unit-jest": "4.4.4",
+    "@vue/cli-plugin-unit-jest": "5.0.6",
     "@vue/cli-service": "4.4.4",
     "@vue/test-utils": "1.0.0-beta.29",
+    "@vue/vue2-jest": "^29.2.5",
     "autoprefixer": "9.5.1",
     "babel-eslint": "10.1.0",
     "babel-jest": "23.6.0",
@@ -62,6 +63,7 @@
     "eslint-plugin-vue": "6.2.2",
     "html-webpack-plugin": "3.2.0",
     "husky": "1.3.1",
+    "jest": "^29.6.2",
     "lint-staged": "8.1.5",
     "mockjs": "1.0.1-beta3",
     "plop": "2.3.0",