title: TypeError: __WEBPACK_IMPORTED_MODULE_0_vue___default.a is not a constructor - for upgrading vue 2.0 to vue 3
body: <p>I am migrating my application vue 2.0 to vue 3.0 . By following the guide, i have done the changes and it is compiled successfully. But, i am getting error in snackbar component. While checking the issue, it was because new Vue() instance. I have upgraded that app Vue 3.0. I am not able to understand how to resolve that.</p>
  <p>Here is my snackbar event js file. Where i was initialized the vue instance.</p>
  <pre><code>    import Vue from 'vue'
  const events = new Vue();
  export default events
  </code></pre>
  <p>This is the snackbar's index.js for reference.</p>
  <pre><code>    import urSnackbar from &quot;./urSnackbar.vue&quot;;
  import snacbkarEvent from &quot;./snackbarEvents&quot;;
  export default {
      install(Vue){
          Vue.component(urSnackbar.name, urSnackbar);
  
          if (this.installed) {
              return
          }
  
          this.installed = true;
  
          const showSnackbar = (params) =&gt; {
              if (typeof params === 'string') {
                  params = { title: '', text: params }
              }
  
              if (typeof params === 'object') {
                  snacbkarEvent.$emit('show-snackbar', params);
              }
          };
          const addSnackbar = (params) =&gt; {
              if (typeof params === 'string') {
                  params = { title: '', text: params }
              }
  
              if (typeof params === 'object') {
                  snacbkarEvent.$emit('add-snackbar', params);
              }
          };
          Vue.prototype.$showSnackbar = showSnackbar;
          Vue.prototype.$addSnackbar = addSnackbar;
      }
  };
  </code></pre>
  <p>This issue reflected while changing the configuration in vue.config.js to resolve the warnings for migration process.</p>
  <p>What i changed in vue.config.js for which this issue occurred</p>
  <pre><code>configureWebpack: {
  resolve: {
    alias: { vue$: 'vue/dist/vue.esm-bundler.js' } } ..... } 
  </code></pre>
  <p>Previously, It was <strong>(vue$: '@vue/compat')</strong>  so i got multiple warnings. For those, i changed as above.</p>
  <p>Can you tell me how i can resolve this issue?</p>