Merge the 2 optimization blocks

Author: pelotom

packages/react-scripts/config/webpack.config.prod.js

@@ -165,6 +165,8 @@ module.exports = {
     // Keep the runtime chunk seperated to enable long term caching
     // https://twitter.com/wSokra/status/969679223278505985
     runtimeChunk: true,
+    // webpack-manifest-plugin currently does not play well with ConcatenatedModule
+    concatenateModules: false,
   },
   resolve: {
     // This allows you to set a fallback for where Webpack should look for modules.
@@ -479,8 +481,4 @@ module.exports = {
   // Turn off performance processing because we utilize
   // our own hints via the FileSizeReporter
   performance: false,
-  optimization: {
-    // webpack-manifest-plugin currently does not play well with ConcatenatedModule
-    concatenateModules: false,
-  },
 };