[blog] Add the "Product" tag to the Pigment CSS post (@danilo-leal) (#42366)

Author: github-actions[bot]

docs/pages/blog/introducing-pigment-css.md

@@ -11,7 +11,7 @@ authors:
     'danilo-leal',
     'oliviertassinari',
   ]
-tags: ['Pigment CSS']
+tags: ['Pigment CSS', 'Product']
 manualCard: true
 ---