chore: Revert parallel Makefile builds (#3918)

This was breaking the release process. Namely it was running
the `gen` targets due to the dependency tree, which was failing
on macOS and Linux runners. This revert can be reverted once
we fix that up.

site/webpack.common.ts

@@ -60,7 +60,6 @@ export const createCommonWebpackConfig = (options?: { skipTypecheck: boolean }):
     // REMARK: It's important to use [contenthash] here to invalidate caches.
     filename: "bundle.[contenthash].js",
     path: path.resolve(__dirname, "out"),
-    clean: false,
   },
 
   // modules specify how different modules are loaded

site/webpack.prod.ts

@@ -47,11 +47,8 @@ export const config: Configuration = {
   output: {
     ...commonWebpackConfig.output,
 
-    // Regenerate the entire out/ directory (except GITKEEP and out/bin/) when
-    // producing production builds
-    clean: {
-      keep: /(GITKEEP|bin\/)/,
-    },
+    // regenerate the entire dist/ directory when producing production builds
+    clean: true,
   },
 
   plugins: [