| dh_clean
| dh_clean: error: Compatibility levels before 7 are no longer supported (level 5 requested)
Also replace `dh_clean -k` with `dh_prep`, to then fix:
| dh_clean -k
| dh_clean: warning: The -k option is not supported in compat 12; use dh_prep instead
| dh_clean: error: This feature was removed in compat 12.