Adding author bio (#22144)

* Update author.yaml

* Add files via upload

Add avatar for contributing blog author Rich Manalang

* Update docs/blog/author.yaml

Co-Authored-By: LB <laurie@gatsbyjs.com>

Co-authored-by: LB <laurie@gatsbyjs.com>

Author: mgienow

docs/blog/author.yaml

@@ -392,3 +392,7 @@
   bio: Teacher, speaker, and community organizer who learned to code via Neopets. Loves theater, karaoke, and dogs.
   avatar: avatars/aisha-blake.jpg
   twitter: "@AishaBlake"
+- id: Rich Manalang
+  bio: Principal developer advocate at LaunchDarkly
+  avatar: avatars/rich-manalang.jpeg
+  twitter: "@rmanalan"