Testing counterpart to trigger post-release updates across repos

[phillxnet]

Follow-up/partner to "Add GitHub Action to trigger post-release updates across repositories #2596 #2597" intended to duplicate the master branch modification in the testing branch. This enables us to use the same semi-automated pre-release prep enabled in master, in testing also. See above referenced issue/pull request set for full details.

Thanks to @FroggyFlox for all the work on this new release mechanism intended to ease our otherwise burgensome version/release numbering normalisation across rocksor-core/rockstor-jslibs/rockstor-rpmbuild.

[phillxnet]

What is required here is likely a cherry pick of commit: b496902 into our testing channel.

We are well on our way to both our final Stable rpm release for this phase (likely 4.6.1-0) and our beginning a new testing phase (5.0.0-0) with work already having been done that significantly deviates testing from our current next stable release: hence the cherry pick proposition. This should aid in our merging of testing into master once we have achieved out next but one Stable state in testing.

[phillxnet]

Closing as
Fixed by #2602