Release cadence and maintenance plans of freedesktop-sdk runtime

[Javier Jardón]

Hi,

After some discussions about different approaches, we would like to
share our current plan for the future freedesktop-sdk flatpak runtime
releases

Note this is not set in stone yet, so please provide feedback or ask
any questions you can have!

- When a new stable release release is done, the changes on that branch
will only be:
  - security updates
  - stable releases (tested carefully); no ABI breaks / API build
breaks.
  - we will try to keep updating that branch as much as we can,
branching only if necessary as previous point


- We release a new major release every year, _only_ if:
  - There is a ABI break with any new component
  - There is a "API build" break (apps might not compile because new
major releases of important packages (GCC))
  - Looking at the GCC and other major project cadences, this is likely
going to happen.


- We will only maintain the current stable release and the previous
one, this means:
  - Stable releases get minimum 2 years of security updates
  - We maintain maximum 3 releases at any given time:
    - Development
    - Stable
    - Old stable

Eventually, if we think is needed and requested by the community, we
could create a LTS release that is supported for longer

This currently lives at [1], any update will be reflected there

Cheers,
Javier

[1] https://gitlab.com/freedesktop-sdk/freedesktop-sdk/wikis/release