feat(starters): add lumen v2 starter. (#9215)

docs/starters.yml

@@ -994,3 +994,22 @@
     - Responsive images with gatsby-image
     - Extensive SEO
     - ESLint & Prettier
+- url: https://lumen-v2.netlify.com/
+  repo: https://github.com/GatsbyCentral/gatsby-v2-starter-lumen
+  description: A Gatsby v2 fork of the lumen starter.
+  tags:
+    - RSS
+    - Disqus
+  features:
+    - Lost Grid.
+    - Beautiful typography inspired by matejlatin/Gutenberg.
+    - Mobile-First approach in development.
+    - Stylesheet built using Sass and BEM-Style naming.
+    - Syntax highlighting in code blocks.
+    - Sidebar menu built using a configuration block.
+    - Archive organized by tags and categories.
+    - Automatic RSS generation.
+    - Automatic Sitemap generation.
+    - Offline support.
+    - Google Analytics support.
+    - Disqus Comments support.