Deprecate Java 8 and move to Java 11

[andre15silva]

Right now we support all Java version starting on Java 8.

Soon, we will have to move towards Java 11 as some of our dependencies are no longer supporting Java 8 (e.g., mockito, spoon).

The issue with this is that some benchmarks, including https://github.com/rjust/defects4j, require Java 8.

[andre15silva]

Required by:

• chore(deps): update dependency org.mockito:mockito-core to v5 #221
• fix(deps): update dependency fr.inria.gforge.spoon:spoon-core to v11 #266