Bump postcss, @vue/cli-plugin-babel, @vue/cli-plugin-eslint and @vue/cli-service

Bumps [postcss](https://github.com/postcss/postcss) to 8.4.31 and updates ancestor dependencies [postcss](https://github.com/postcss/postcss), [@vue/cli-plugin-babel](https://github.com/vuejs/vue-cli/tree/HEAD/packages/@vue/cli-plugin-babel), [@vue/cli-plugin-eslint](https://github.com/vuejs/vue-cli/tree/HEAD/packages/@vue/cli-plugin-eslint) and [@vue/cli-service](https://github.com/vuejs/vue-cli/tree/HEAD/packages/@vue/cli-service). These dependencies need to be updated together.


Updates `postcss` from 7.0.39 to 8.4.31
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss/compare/7.0.39...8.4.31)

Updates `@vue/cli-plugin-babel` from 4.5.15 to 5.0.8
- [Release notes](https://github.com/vuejs/vue-cli/releases)
- [Changelog](https://github.com/vuejs/vue-cli/blob/dev/CHANGELOG.md)
- [Commits](https://github.com/vuejs/vue-cli/commits/v5.0.8/packages/@vue/cli-plugin-babel)

Updates `@vue/cli-plugin-eslint` from 4.5.15 to 5.0.8
- [Release notes](https://github.com/vuejs/vue-cli/releases)
- [Changelog](https://github.com/vuejs/vue-cli/blob/dev/CHANGELOG.md)
- [Commits](https://github.com/vuejs/vue-cli/commits/v5.0.8/packages/@vue/cli-plugin-eslint)

Updates `@vue/cli-service` from 4.5.15 to 5.0.8
- [Release notes](https://github.com/vuejs/vue-cli/releases)
- [Changelog](https://github.com/vuejs/vue-cli/blob/dev/CHANGELOG.md)
- [Commits](https://github.com/vuejs/vue-cli/commits/v5.0.8/packages/@vue/cli-service)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
- dependency-name: "@vue/cli-plugin-babel"
  dependency-type: direct:development
- dependency-name: "@vue/cli-plugin-eslint"
  dependency-type: direct:development
- dependency-name: "@vue/cli-service"
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

quiz-app/package.json

@@ -14,9 +14,9 @@
     "vue-router": "^3.5.3"
   },
   "devDependencies": {
-    "@vue/cli-plugin-babel": "~4.5.0",
+    "@vue/cli-plugin-babel": "~5.0.8",
-    "@vue/cli-plugin-eslint": "~4.5.0",
+    "@vue/cli-plugin-eslint": "~5.0.8",
-    "@vue/cli-service": "~4.5.0",
+    "@vue/cli-service": "~5.0.8",
     "babel-eslint": "^10.1.0",
     "eslint": "^6.7.2",
     "eslint-plugin-vue": "^6.2.2",