Bump @vue/cli-service from 3.12.1 to 4.0.4

Bumps [@vue/cli-service](https://github.com/vuejs/vue-cli/tree/HEAD/packages/@vue/cli-service) from 3.12.1 to 4.0.4.
- [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/v4.0.4/packages/@vue/cli-service)

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

package.json

@@ -17,7 +17,7 @@
     "@fullhuman/postcss-purgecss": "^1.3.0",
     "@vue/cli-plugin-babel": "^3.11.0",
     "@vue/cli-plugin-eslint": "^3.11.0",
-    "@vue/cli-service": "^3.11.0",
+    "@vue/cli-service": "^4.0.4",
     "@vue/eslint-config-standard": "^4.0.0",
     "babel-eslint": "^10.0.3",
     "eslint": "^5.8.0",