Use f-strings

[eumiro]

Replace % and .format syntax with f-strings where appropriate. Also replace the text indentation code with stdlib's textwrap.indent method call.

[amoffatgmi]

Cool, lgtm

[amoffat]

Please don't force push @eumiro. It hides your changes and means I need to review them from the start again. Only add new commits so that the audit trail of what changed is clear.

Force push invalidated changes

[eumiro]

Sorry for the forcepush. I had difficulties running tests on my host, so I waited for the CI (that you had to approve). The only change I did now was the black reformat of one line.

In the first CI run I also saw one test fail and wanted to check it after the re-run of CI.

[ecederstrand]

@eumiro There's a single test failure in test_change_log_message. Can you have a look at that?

[ecederstrand]

Thanks for the contribution!