Update to Phoenix 1.6.6

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

config/dev.exs

@@ -21,13 +21,8 @@ config :clip, ClipWeb.Endpoint,
   code_reloader: true,
   check_origin: false,
   watchers: [
-    node: [
-      "node_modules/webpack/bin/webpack.js",
-      "--mode",
-      "development",
-      "--watch-stdin",
-      cd: Path.expand("../assets", __DIR__)
-    ]
+    # Start the esbuild watcher by calling Esbuild.install_and_run(:default, args)
+    esbuild: {Esbuild, :install_and_run, [:default, ~w(--sourcemap=inline --watch)]}
   ]
 
 # ## SSL Support