feat: run optimize against assets added later by plugins (webpack@5 only)

Author: alexander-akait

test/CssMinimizerPlugin.test.js

@@ -1125,12 +1125,12 @@ describe('CssMinimizerPlugin', () => {
           ],
         },
       });
+
       new CssMinimizerPlugin({
         minimizerOptions: {
           preset: ['default', { discardEmpty: false }],
         },
       }).apply(compiler);
-
       new EmitNewAsset({ name: 'newFile.css' }).apply(compiler);
 
       const stats = await compile(compiler);

test/__snapshots__/CssMinimizerPlugin.test.js.snap.webpack5

@@ -59,6 +59,16 @@ exports[`CssMinimizerPlugin should respect the hash options #1: errors 1`] = `Ar
 
 exports[`CssMinimizerPlugin should respect the hash options #1: warnings 1`] = `Array []`;
 
+exports[`CssMinimizerPlugin should run plugin against assets added later by plugins: assets 1`] = `
+Object {
+  "newFile.css": ".a{display:block;color:coral}",
+}
+`;
+
+exports[`CssMinimizerPlugin should run plugin against assets added later by plugins: errors 1`] = `Array []`;
+
+exports[`CssMinimizerPlugin should run plugin against assets added later by plugins: warnings 1`] = `Array []`;
+
 exports[`CssMinimizerPlugin should throw error from postcss: error 1`] = `
 Array [
   "Error: foo.css from Css Minimizer