VOL-4964 - Update core contributors list

Last two pull requests including VERSION=2.12.0 did not initiate publishing
content to docs.voltha.org.  Create another pull request with release VERSION
string and modified content to see if that will trigger a release.

Change-Id: Ica3edca4ba2ca5bf7b8fc75eb4c1f688a671a456
diff --git a/howto/edit_voltha_docs.rst b/howto/edit_voltha_docs.rst
index 540b734..32bcf9d 100644
--- a/howto/edit_voltha_docs.rst
+++ b/howto/edit_voltha_docs.rst
@@ -34,7 +34,7 @@
 Writing Docs
 """"""""""""
 
-Docs written using sphinx: http://www.sphinx-doc.org
+Docs written using sphinx: https://www.sphinx-doc.org/en/master/
 
 Documentation is done in reStructuredText or Markdown, but only ``.rst`` files
 can contain embedded diagrams.