Update links to the docs for 2.20 GA
Update links to the docs for 2.20 GA

pulp/pulpproject.org,bmbouter/pulpproject.org,bmbouter/pulpproject.org,dkliban/pulpproject.org,dkliban/pulpproject.org,dkliban/pulpproject.org,pulp/pulpproject.org,dkliban/pulpproject.org,pulp/pulpproject.org,bmbouter/pulpproject.org,pulp/pulpproject.org,bmbouter/pulpproject.org