Assign a smaller number of reviewers to PRs (#3543)

Using a smaller number of reviewers should increase responsiveness and
accountability.

Signed-off-by: Nolan Brubaker <brubakern@vmware.com>

.github/auto_assign.yml

@@ -1,8 +1,9 @@
 addReviewers: true
 addAssignees: author
 
-# Set this to the length of the reviewers list because the default was not including everyone
-numberOfReviewers: 6
+# Only require 2, random reviewers.
+# TODO expand this to support using reviewGroups
+numberOfReviewers: 2
 
 reviewers:
   - nrb
@@ -10,4 +11,4 @@ reviewers:
   - carlisia
   - zubron
   - dsu-igeek
-  - jenting
+  - jenting