Fix Cygwin CI after #32841

[mkoeppe]

📚 Description

Cygwin workflows were mangled by a bad merge, leading to syntax errors even whenever the workflow is parsed.

Here we fix this; note that the Cygwin workflow is still not functional afterward (the first step, installation of Cygwin with choco, fails). But this will only affect builds of releases and does not happen for PR CI runs.

Closes #35048

📝 Checklist

• I have made sure that the title is self-explanatory and the description concisely explains the PR.
• I have linked an issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

⌛ Dependencies

[roed314]

This is certainly an improvement (since the workflow starts now), but it still seems to be failing: https://github.com/sagemath/sage/actions/runs/4137773690.

[roed314]

You should probably also merge develop.

[mkoeppe]

This is certainly an improvement (since the workflow starts now), but it still seems to be failing

Yes, as noted in the PR description.
Fixing the workflow won't be very useful at the moment – I don't plan to work on the Cygwin port any more, and no one else has stepped up. See https://github.com/sagemath/sage/wiki/ReleaseTours-sage-9.7#sources

[mkoeppe]

You should probably also merge develop.

No need; nothing else touches these files.

[roed314]

Ok.

[roed314]

Works for me: I'm no longer getting syntax errors on the workflow.

[mkoeppe]

Thanks, David!

[dimpase]

Can we have a careful rebase here? I don't want to accidentally destroy fix-develop.

[dimpase]

We can also merge directly into develop... But pick one way.

[mkoeppe]

What is fix-develop?

[mkoeppe]

Oh I see, I created the branch in sagemath/sage by accident. Will delete as soon as this PR is merged.

[tobiasdiez]

@dimpase If you choose "Squash" in the merge button dropdown, then the branch history of develop is a bit cleaner than with a classical merge.