Allow ability to mark release as _not_ being the latest

[gep13]

Detailed Description

We need the ability to be able to mark a release as not being the latest release available.

This should be possible from a few places:

• from the GitReleaseManager.yaml file
• from the command line

The default should remain that the generated release should be marked as latest.

Context

By default, when you create a release, at least on GitHub, it is immediately marked as being the latest available. There are times when this is not desirable, since for example, you might be doing a release from a support branch.

Possible Implementation

This is sort of discussed above already

Your Environment

N/A