Inline the webpack runtime chunk (facebook#5058)

config/webpack.config.prod.js

@@ -12,6 +12,7 @@ const autoprefixer = require('autoprefixer');
 const path = require('path');
 const webpack = require('webpack');
 const HtmlWebpackPlugin = require('html-webpack-plugin');
+const InlineChunkHtmlPlugin = require('react-dev-utils/InlineChunkHtmlPlugin');
 const TerserPlugin = require('terser-webpack-plugin');
 const MiniCssExtractPlugin = require('mini-css-extract-plugin');
 const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
@@ -433,6 +434,9 @@ module.exports = {
         minifyURLs: true,
       },
     }),
+    // Inlines the webpack runtime script. This script is too small to warrant
+    // a network request.
+    new InlineChunkHtmlPlugin(HtmlWebpackPlugin, [/runtime~.+[.]js/]),
     // Makes some environment variables available in index.html.
     // The public URL is available as %PUBLIC_URL% in index.html, e.g.:
     // <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">