Define an initial release procedure

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

RELEASE.md

@@ -0,0 +1,19 @@
+# Release procedure
+
+1. Create a tag for the release of the format v4.MINOR.PATCH,
+   following the format specified in <MAINTAINING.md>.
+2. Verify that the associated release action has concluded.
+3. Verify that the expected artifacts were built and successfully
+   attached to the matching release. This includes the source tarball
+   and RPMs for Suse and Rocky Linux.
+4. Update the release notes for the release, expanding on the relevant
+   contents from <CHANGELOG.md>.
+5. Confirm the correct values for the pre-release and latest release
+   flags.
+6. Publish the release.
+7. Announce the release as a [post][1] to warewulf.org/news, linking
+   to the GitHub release.
+8. Announce the release on the Warewulf Slack, linking to the
+   warewulf.org/news post.
+
+[1]: https://github.com/warewulf/warewulf.org/tree/main/src/posts