chore(package): update @vue/cli-service to version 4.1.2

Closes #39

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "@vue/cli-plugin-eslint": "^3.5.0",
     "@vue/cli-plugin-typescript": "^3.5.0",
     "@vue/cli-plugin-unit-jest": "^3.5.1",
-    "@vue/cli-service": "^3.5.0",
+    "@vue/cli-service": "^4.1.2",
     "@vue/eslint-config-prettier": "^4.0.1",
     "@vue/eslint-config-typescript": "^4.0.0",
     "babel-eslint": "^10.0.1",