ci: speed up code-coverage jobs

Plus some documentation updates

Change-Id: I6fd2b04e22bca6c3d6e36e78d1995220e261206b
Refs: #3809
diff --git a/docs/README.rst b/docs/README.rst
index c1e0bba..b58f125 100644
--- a/docs/README.rst
+++ b/docs/README.rst
@@ -19,4 +19,4 @@
    NDN <https://github.com/named-data/ndn-traffic-generator>`__
 
 Please submit any bugs or issues to the `ndn-cxx issue tracker
-<http://redmine.named-data.net/projects/ndn-cxx/issues>`__.
+<https://redmine.named-data.net/projects/ndn-cxx/issues>`__.