Tailwind example only run PurgeCSS in production (#9846)

* Tailwind example only run PurgeCSS in production

* Apply lint
Co-authored-by: NJoe Haddad <timer150@gmail.com>

examples/with-tailwindcss/postcss.config.js

@@ -2,13 +2,14 @@ module.exports = {
   plugins: [
     require('postcss-easy-import'),
     require('tailwindcss'),
-    require('@fullhuman/postcss-purgecss')({
-      content: [
-        './pages/**/*.{js,jsx,ts,tsx}',
-        './components/**/*.{js,jsx,ts,tsx}',
-      ],
-      defaultExtractor: content => content.match(/[A-Za-z0-9-_:/]+/g) || [],
-    }),
+    process.env.NODE_ENV === 'production' &&
+      require('@fullhuman/postcss-purgecss')({
+        content: [
+          './pages/**/*.{js,jsx,ts,tsx}',
+          './components/**/*.{js,jsx,ts,tsx}',
+        ],
+        defaultExtractor: content => content.match(/[A-Za-z0-9-_:/]+/g) || [],
+      }),
     require('autoprefixer'),
     require('cssnano'),
   ],