Update to Phoenix 1.6.6

Update by applying https://gist.github.com/chrismccord/2ab350f154235ad4a4d0f4de6decba7b
JS hooks not working yet.

assets/js/app.js

@@ -1,7 +1,7 @@
 // We need to import the CSS so that webpack will load it.
 // The MiniCssExtractPlugin is used to separate it out into
 // its own CSS file.
-import "../css/app.scss"
+import "../css/app.css"
 
 // webpack automatically bundles all modules in your
 // entry points. Those entry points can be configured
@@ -25,6 +25,7 @@ Hooks.SnippetInput = {
   updated(){
     this.el.value = this.el.dataset.updatedVal
     copy_func()
+    console.log('yeah!')
   }
 }