Trigger non-core connector tests when core or DDL parser module are changed

As we move more and more towards multiple github repository usage it is necessary to solve a problem of cross repository builds.

IMHO the best approach would be

• build and test incubator and vitess repos as aa separate workflow in main repository when debezium-core is updated. This will verify that the core changes don't break compatibility with additional connectors
• extend the addiitonal connector repo in that way that
  • upon the connector build the PR workflow will check if there is a PR branch with DBZ-xxx commit message prefix as the one in incubator repo
  • if yes the local build of core repo will be done of this branch. This will verify that connectors are working with updated core
  • if not then the build will be done off master