Release v0.2.2

Test: verify custom similarity flag is forwarded in DiffCreator

Add a unit test to ensure `DiffCreator.get_full_working_diff` passes the `similarity` argument as the `-M` flag to the underlying git diff command.
- Introduce `test_get_full_working_diff_custom_similarity`
- Mock git binary output and binary file detection
- Invoke `get_full_working_diff` with `similarity=87`
- Assert `run_git_binary_out` is called with `["diff", "base", "new", "--binary", "--unified=0", "-M87", "--"]`