Update homepage

Since change I5cbf7b5cfea349a0bd72d2abee40710175cf5b2f, this repo
publishes to https://jenkins-job-builder.readthedocs.io/en/latest/ ,
let's update the links for this.

Change-Id: I08f8dd992ee1b6360f3d226cb668cda7f4242b8a

README.rst

@@ -13,7 +13,7 @@ To install::
 
 Online documentation:
 
-* http://docs.openstack.org/infra/jenkins-job-builder/
+* https://jenkins-job-builder.readthedocs.io/en/latest/
 
 Developers
 ----------

jenkins_jobs/modules/publishers.py

@@ -7318,7 +7318,7 @@ def hipchat(registry, xml_parent, data):
     <Hipchat+Plugin>` version >=1.9
 
     Please see documentation for older plugin version
-    http://docs.openstack.org/infra/jenkins-job-builder/hipchat.html
+    https://jenkins-job-builder.readthedocs.io/en/latest/hipchat.html
 
     :arg str token: This will override the default auth token (optional)
     :arg list rooms: list of HipChat rooms to post messages to, overrides

setup.cfg

@@ -11,7 +11,7 @@ author-email = jenkins-job-builder@googlegroups.com
 summary = Manage Jenkins jobs with YAML
 description-file = README.rst
 license = Apache License, Version 2.0
-home-page = https://docs.openstack.org/infra/jenkins-job-builder/
+home-page = https://jenkins-job-builder.readthedocs.io/en/latest/
 classifier =
     Topic :: Utilities
     Environment :: Console