Create release branch cassandra-5.0

Figure out what needs to be done beyond the following…

1. Create release branch

git switch -c cassandra-5.0 trunk
git push --set-upstream origin cassandra-5.0

2. Bump trunk's version

git switch trunk
# increment version to 5.1
edit build.xml debian/changelog CHANGES.txt NEWS.txt

2a. Update jvm-dtest supported upgrade paths, and dtest jar generation (both circleci and in-tree scripts), in both cassandra-5.0 and trunk branches:

• https://github.com/apache/cassandra/blob/trunk/test/distributed/org/apache/cassandra/distributed/upgrade/UpgradeTestBase.java#L85-L96
• https://github.com/apache/cassandra/blob/trunk/.circleci/config.yml#L2374
• https://github.com/apache/cassandra/blob/trunk/.build/run-tests.sh#L85

2b. Bump versions in cassandra-5.0 branch

• doc/antora.yml
• build.xml, append "-alpha1" to `base.version`

3. Add `5.0-alpha`, `5.0-alpha1`, `5.0-beta`, `5.0-rc`, `5.0.x` and `5.1` to jira versions
(no existing tickets will be changed - assignees need to change appropriate bugs from 5.x to what is appropriate…)

4. Update docker images to include cassandra-5.0
(Docker images also need to be deployed)

5. Add pipeline to ci-cassandra
https://github.com/apache/cassandra-builds/blob/trunk/jenkins-dsl/cassandra_job_dsl_seed.groovy#L51

6. Add dtest version and upgrade paths

• https://github.com/apache/cassandra-dtest/blob/trunk/upgrade_tests/upgrade_manifest.py
• https://github.com/apache/cassandra-builds/blob/trunk/build-scripts/cassandra-test.sh#L41

7. Update how_to_commit documentation
https://github.com/apache/cassandra-website/blob/trunk/site-content/source/modules/ROOT/pages/development/how_to_commit.adoc

8. Update website CI to trigger off cassandra-5.0 builds

• https://github.com/apache/cassandra-builds/commit/1fc9b5ee71dc37e1145f276ead5c680c6b3fe3db

9. Update website to build new branches

• https://github.com/apache/cassandra-website/blob/trunk/site-content/Dockerfile#L93