Old actions use deprecated node 12
- cache v2 -> v3
- checkout v2 -> v3
- download-artifact v2 -> v3
- setup-java v2 -> v3
- disable access to GITHUB_TOKEN
- don't store credentials with checkout
- don't execute build for PR from local repository branches - we have build on push event
* Fix plexus gav
* Install maven instead of just building it
The plugins need to be available in the local repo, else the build may download old snapshots