CI: false negatives on "OptaPlanner Persistence JPA CI" Github Action because doesn't rebuild optaplanner-core etc

This build failed
https://github.com/kiegroup/optaplanner/pull/819/checks?check_run_id=827171022
for this PR:
https://github.com/kiegroup/optaplanner/pull/819
that changes the pom.xml <version> of master.

I believe that the "OptaPlanner Persistence JPA CI" Github Action will report false negatives for any changes that:

• changes the optaplanner version (think mbiarnes's releases, but those don't go through PR's)
• changes a method name in optaplanner-core that is used in optaplanner-persistence-jpa.

To reproduce:

• Look for a non-public api method in optaplanner-core used by optaplanner-persistence-jpa and refactor rename it to "foo". Submit that PR as a test. That job will fail because it doesn't build optaplanner-core first: instead it grabs the old optaplanner-core jar from nexus snapshots, which doesn't have a "foo" method yet.

Other way to reproduce:

• Replace all 8.0.0-SNAPSHOT with 8.test-SNAPSHOT in all poms and submit that PR as a test. That job will fail because it doesn't build optaplanner-core first, so it can't find it during artifact resolution of maven.

Same applies to optaplanner-parent changes etc.