React 17 RC release blog post (#3185)

* New blog post

* Apply suggestions from code review

Co-authored-by: Toru Kobayashi <koba0004@gmail.com>

* Add an illustration by @rachelnabors

* Co-credit the post

* Add changelog

* say it again

* Add a section

Co-authored-by: Toru Kobayashi <koba0004@gmail.com>
Co-authored-by: Rachel Nabors <rachelnabors@gmail.com>

Author: 3 people

content/authors.yml

@@ -61,6 +61,9 @@ nhunzaker:
 petehunt:
   name: Pete Hunt
   url: https://twitter.com/floydophone
+rachelnabors:
+  name: Rachel Nabors
+  url: https://twitter.com/rachelnabors
 schrockn:
   name: Nick Schrock
   url: https://twitter.com/schrockn
@@ -93,4 +96,4 @@ zpao:
   url: https://twitter.com/zpao
 tomocchino:
   name: Tom Occhino
-  url: https://twitter.com/tomocchino
+  url: https://twitter.com/tomocchino