Follow-up: Branch github.com/openjdk/jdk for stabilization (instead of fork)

[Volker Simonis]

Hello OpenJDK Contributors,

It's now more than a year that we we've switched from GitHub forks to
branches for stabilization releases [1]. Overall, the transition was
smooth and successful, but I think there are a few minor follow-ups
which still need to be completed:

1. "JEP 3: JDK Release Process" [2] still described the old, forking
workflow (i.e. "We fork the main-line repository into a stabilization
repository, jdk/jdk$N"). This should be corrected.
2. The new stabilization branches have the same, unmodified README.md
file like the main branch which is a little confusing. I propose that
every time we create a new stabilization branch the first change in
that new branch should update the README.md file (similar to what the
community updates repositories are already doing [5]) with at least
the following changes:
- "Welcome to the JDK!" -> "Welcome to the JDK <NN>!"
- Add a link to the corresponding release page (i.e.
https://openjdk.org/projects/jdk/<NN>/)
- The links to the build instructions should be changed to point to
the build instructions in the corresponding branch otherwise they
might eventually point to a newer, incompatible version
3. The last one is more of a usability issue and I currently don't
know how to solve it, but maybe someone else has an idea? Recently,
GitHub changed the sorting order of branches in the pull-down menu for
selecting a branch on their web page from alphabetical to "last
recently used" [3]. This now makes it almost impossible to find the
stabilization branches because they are buried somewhere in the middle
of a ton of "pr/xxxx" branches.

Finally I CC this message to jdk-updates-dev at openjdk.org as a reminder
that the time might be ripe now to consider branching instead of
forking for the update projects as well? Maybe we can start slowly by
first getting rid of the "jdkNNu-dev" forks and use branches for this
in the existing "jdkNNu" repositories as Oracle already does for the
first two updates they do (e.g. [4])

Best regards,
Volker

[1] https://mail.openjdk.org/pipermail/jdk-dev/2024-March/008834.html
[2] https://openjdk.org/jeps/3#Overview
[3] https://github.com/orgs/community/discussions/161489
[4] https://github.com/openjdk/jdk21u/tree/jdk21.0.1
[5] https://github.com/openjdk/jdk21u/commit/22d5e0d1f8849410abe40165b58f45f5e4293884