[Gluster-Maintainers] Proposal (rfc): Upstream release versions and cadence

[Shyam Ranganathan]

## Summary
This proposal is to change the upstream release cadence from quarterly
to every 4 months and to have all releases as long term maintenance
releases. IOW, just maintained releases, and drop long/short terminology.

Further, it is to start numbering releases with just a MAJOR version
rather than a x.y.z format that we currently employ.

## Reasons for the change
- Avoid stalling/planning-for features awaiting a major release once
every 4 years
- Remove stigma around a set of features defining release MAJOR version
change
- Remove LTM/STM and surrounding confusion (if any) and just do releases
- Reduce number of releases each year (including update releases)
- Retain reduced length between releases, to gain traction on upcoming
features

## Details
### Release cadence
- Release every 4 months
- Makes up 3 releases each year
- Each release is maintained till n+3 is released (IOW, for a year)
- Gives community users a year on a release before an upgrade needs to
be performed
- Retain backward compatibility across releases, for ease of
migrations/upgrades

### Release updates
- First 3 release updates (which are bug fixes) are done every month
- Further release updates are made once every 2 months till EOL
- At any given point there would be 3 releases getting updates, hence
update calendar can remain the same (10th/20th/30th of the month)
- Out of band releases for critical issues or vulnerabilities will be
done on demand

### Release versioning
- Version releases using a monotonic increasing number starting at 5
    - Hence release-5, release-6, …
    - VERSION is 5/6/...
- Use minor numbers for updates, like 5.x or 6.x, x monotonically
increasing every update
- RPM versions would look like <package>.<VERSION.x>-<BUILD>.<DISTRO>.<ARCH>
    - Used to look like <package>.<X.Y.Z>-<BUILD>.<DISTRO>.<ARCH>

### Note on op-version
- Delink op-version from package/release versions
- Use op-version for operating reasons and use a different/alternate
numbering scheme
- Rethink op-versions as suitable for this purpose

Comments, alternatives welcome, I will keep this open for a week and
announce this to the users and other lists post that.

Thanks,
Shyam