[Operator] Preparing for the v0.5.0 release

[Houston Putman <ho...@apache.org>]

Hey everyone,

We are getting close to closing out all of the issues currently marked for
the v0.5.0 Solr Operator release. We want to get this release out as soon
as possible, in order to support v1.22 Kubernetes clusters.

Here is a link to the milestone, which shows that all but one (possibly
unneeded) issue have linked PRs. Hopefully these PRs can be finished, and
merged by the end of next week. After that I plan on cutting the release
and preparing the release candidate.

https://github.com/apache/solr-operator/milestone/5

If you have any other issues that need to make it in, please create issues
with the v0.5.0 milestone sometime early next week!

- Houston