Add support for the Pijul VCS

[korrat]

Pijul is a new VCS based on a theory of commutative patches. This commit adds support for Pijul to reuse-tool by implementing VCSStrategyPijul.

[carmenbianca]

Hi @korrat

Thanks a heap for this PR! It looks pretty good. I fixed up some things that I swore I would fix whenever the third VCS is added to the tool (to reduce having to write if statements everywhere).

Before this can be merged, though, it needs a few things:

• Some tests added
  • This needs a pijul_repository fixture in conftest, I think. I'm not sure if it does the rest automagically.
• A change log entry.
• Add yourself to AUTHORS.rst.
• edit: Pijul needs to be installed in the CI for it to be tested.

Could you take care of these?

[korrat]

Yes, I will take care of that!

[carmenbianca]

(Did a sneaky force push to fix a test I caused to fail)

[korrat]

I've done the first three things, and I think I also finished step 4, but let's wait on the workflows to confirm.

I've also rebased and force-pushed the branch to solve the conflict with main.

[carmenbianca]

Awesome work @korrat !

I will review this soon. Thank you so much for your contribution :)

[korrat]

I fixed the installation of Pijul and the failing tests. Let me know if you would like me to rebase & squash the fixup commits (or everything).

And thanks a lot for the smooth contribution experience!

[mxmehl]

May I add that we also should mention an additional VCS on the website: https://reuse.software/faq/#no-git

VCSs are also mentioned in the README IIRC.

[carmenbianca]

LGTM. I moved the Pijul tests to their own workflow. Thanks a lot for this contribution @korrat

[korrat]

Thank you very much for the great experience!