[Podman] process change to releases and fedora packaging

Hi Folks, We wanted to make the wider podman audience aware of a small change we are making for podman releases starting with 1.6. Prior to each release, we will be tagging a release.rc1 (release candidate). The idea here is we want to allow for some of our sister teams to be able to test a release prior to cutting it. These release candidates will be automatically built in Fedora rawhide and the previous two Fedora versions (generally). However, no bodhi will be created for the rc's; they are reserved for actual releases. We are hoping this helps us improve our releases and make our process smoother. Brent