GitHub action for "Build Testing Workflow" is using old artifacts and not building missing dependencies

GitHub action for "Build Testing Workflow" is using old artifacts and not building missing dependencies. This leads to broken builds that miss artifacts (like for debezium-assembly-descriptors) or does not create a fresh build for an updated debezium-core.

We have to make sure that either we stop using multi-module builds from using Maven Cache or guarantee that proper artifact caching is used.

see:

https://github.com/debezium/debezium/pull/2018#discussion_r544432542

https://github.com/debezium/debezium/pull/1920/files#r539168346

Currently we have 2 issues: Either the build is failing because an artifact is missing in the Maven cache repo and the job doesn't build that dependency (like here with the missing `debezium-assembly-descriptors` jar. Or the build has a cached jar, but in-fact should use new updated code instead of the old cached one.

Also see the valuable comments here: https://github.com/debezium/debezium/pull/2018#discussion_r545578544