Merge pull request #2320 from cylc/samuel-denton-patch-1

Update CONTRIBUTING.md

Author: oliver-sanders

CONTRIBUTING.md

@@ -62,6 +62,7 @@ below.
  - Mark Dawson
  - Min RK
  - Harleen Kaur
+ - Samuel Denton
 <!-- end-shortlog -->
 
 (All contributors are identifiable with email addresses in the git version