Ionic vue plugin

I am trying to create an ionic-vue app following this post but I get Cannot convert undefined or null to object error, when I register @ionic/vue plugin in main.js.

import Vue from 'vue'
import App from './App.vue'
import router from './router'

import Ionic from '@ionic/vue'
import '@ionic/core/css/ionic.bundle.css'

Vue.use(Ionic)
Vue.config.productionTip = false

new Vue({
  router,
  render: h => h(App)
}).$mount('#app')

Package.json

  "dependencies": {
    "@ionic/core": "^4.6.2",
    "@ionic/vue": "0.0.4",
    "core-js": "^2.6.5",
    "vue": "^2.6.10",
    "vue-router": "^3.0.3"
  },
  "devDependencies": {
    "@vue/cli-plugin-babel": "^3.9.0",
    "@vue/cli-plugin-eslint": "^3.9.0",
    "@vue/cli-service": "^3.9.0",
    "babel-eslint": "^10.0.1",
    "eslint": "^5.16.0",
    "eslint-plugin-vue": "^5.0.0",
    "vue-template-compiler": "^2.6.10"
  }

It seems to be a problem with ionicons. According to this thread adding ionicons@4.5.9-1 fixes the issue.