Upgrade Vue Cli

babel.config.js

@@ -1,5 +1,5 @@
 module.exports = {
   presets: [
-    '@vue/app'
+    '@vue/cli-plugin-babel/preset'
   ]
 }

package.json

@@ -8,7 +8,7 @@
   },
   "dependencies": {
     "browser-id3-writer": "^4.3.0",
-    "core-js": "^2.6.10",
+    "core-js": "^3.4.3",
     "crypto-js": "^3.1.9-1",
     "element-ui": "^2.13.0",
     "music-metadata-browser": "^1.8.1",
@@ -16,9 +16,9 @@
     "vue": "^2.6.10"
   },
   "devDependencies": {
-    "@vue/cli-plugin-babel": "^3.11.0",
+    "@vue/cli-plugin-babel": "^4.1.1",
-    "@vue/cli-plugin-pwa": "^3.11.0",
+    "@vue/cli-plugin-pwa": "^4.1.1",
-    "@vue/cli-service": "^3.11.0",
+    "@vue/cli-service": "^4.1.1",
     "babel-plugin-component": "^1.1.1",
     "vue-cli-plugin-element": "^1.0.1",
     "vue-template-compiler": "^2.6.10"