Prepare new stable/yoga release

The previous release was not uploaded to puppetforge properly, because
of size limit. It turned out we included the irrelevant files such as
.git and that causes too large archive.

This attempts to create a new release with the .pdkignore file added,
to exclude unnecessary files.

Change-Id: I1ae691ed3a9893401ea4ec2a808287033e6bc633

metadata.json

@@ -71,5 +71,5 @@
     ],
     "source": "https://opendev.org/openstack/puppet-nova.git",
     "summary": "Puppet module for OpenStack Nova",
-    "version": "20.4.1"
+    "version": "20.4.2"
 }