Add 2.12 nightly docs link
Add 2.12 nightly docs link

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