Fix docs publishing error "The unauthenticated git protocol on port 9418 is no longer supported."

Author: rmk135

requirements-doc.txt

@@ -1,5 +1,5 @@
 # TODO: unpin 3.5.0 when this bug is fixed: https://github.com/sphinx-doc/sphinx/issues/8885
 sphinx<3.5.0
--e git://github.com/rmk135/sphinxcontrib-disqus.git#egg=sphinxcontrib-disqus
+-e git+https://github.com/rmk135/sphinxcontrib-disqus.git#egg=sphinxcontrib-disqus
 
 -r requirements-ext.txt