migrate to vue-cli 4

- needed to have fix vuejs/eslint-plugin-vue#910
- adapt to core-js@3.x

package.json

@@ -16,9 +16,13 @@
     "vue-translate-plugin": "^1.2.0"
   },
   "devDependencies": {
-    "@vue/cli-plugin-babel": "^3.4.0",
-    "@vue/cli-plugin-eslint": "^3.4.0",
-    "@vue/cli-service": "^3.4.0",
+    "@vue/cli-plugin-babel": "^4.1.2",
+    "@vue/cli-plugin-eslint": "^4.1.2",
+    "@vue/cli-service": "^4.1.2",
+    "@vue/eslint-config-standard": "^4.0.0",
+    "babel-eslint": "^10.0.3",
+    "eslint": "^5.16.0",
+    "eslint-plugin-vue": "^5.0.0",
     "vue-template-compiler": "^2.6.6"
   },
   "postcss": {

src/main.js

@@ -7,8 +7,8 @@ import router from './router'
 import Translations from './translations'
 import GlobalMixin from './GlobalMixin'
 import AsyncComputed from 'vue-async-computed'
-import 'core-js/modules/es6.promise'; // needed by vue-async-computed (why does it not go through babel transform-runtime?)
-import 'core-js/modules/es6.array.find';
+import 'core-js/modules/es.promise'; // needed by vue-async-computed (why does it not go through babel transform-runtime?)
+import 'core-js/modules/es.array.find';
 import './directives';
 
 Vue.use(AsyncComputed)