Fix broken tests in GH Actions

[rwanderc]

Some tests do not run in GH Actions for Java 8 but runs for the other Java versions or even run in forks.
https://github.com/freenowtech/spring-multirabbit/runs/2049994398 failed in Java 8.
https://github.com/freenowtech/spring-multirabbit/runs/2050015938 ran successfully in Java 11 & 14.

Locally, all tests pass successfully. Forks of the repository can run the test perfectly for all java versions.
It might be related to some sort of caching of Actions but yet I don't know the