chore(package): update @vue/cli-plugin-babel to version 4.0.4

Closes #24

Author: greenkeeper[bot]

package.json

@@ -20,7 +20,7 @@
     "vue": "^2.6.10"
   },
   "devDependencies": {
-    "@vue/cli-plugin-babel": "^3.6.0",
+    "@vue/cli-plugin-babel": "^4.0.4",
     "cz-conventional-changelog": "^3.0.0",
     "@vue/cli-plugin-eslint": "^3.6.0",
     "@vue/cli-plugin-unit-jest": "^3.6.0",