Merge pull request #17720 from alifrumin/5.27.0-releasenotes

[NFC] 5.27 release notes - first pass

contributor-key.yml

@@ -379,6 +379,9 @@
 
 - github      : don-alejandro-z
 
+- github      : jmdh
+  name        : Dominic Hargreaves
+
 - name        : Samuel Haskell
   jira        : dotsam
 
@@ -994,6 +997,10 @@
 - github      : mecachisenros
   name        : Andrei Mondoc
 
+- github      : megaphonetech-dennis
+  name        : Dennis P. Osorio
+  organization: Megaphone Technology Consulting
+
 - github      : mepps
   name        : Maggie Epps
   organization: Wikimedia Foundation