Revert "Set https for webpack dev server."

This reverts commit a8621f34.

javascript/webpack.config.dev.js

@@ -7,7 +7,7 @@ module.exports = merge(common, {
   mode: 'development',
   devServer: {
     contentBase: './dist',
-    https: true,
+    // hot: true,
     port: 9000,
     headers: {
       'Access-Control-Allow-Origin': '*'