Only install pyroma 4.0 in Cygwin

[radarhere]

pyroma 4.1 was released yesterday, and since then Cygwin has started failing in main - https://github.com/python-pillow/Pillow/actions/runs/3544062653

[hugovk]

I'd rather we figure out the root cause rather than pinning (indefinitely?) pyroma, alternatively we could skip pyroma for Cygwin altogether.

I wonder if this is another setuptools thing? pyroma now requires setuptools>=61.0.0:

regebro/pyroma@4.0...4.1

From the logs:

Collecting setuptools>=61.0.0
  Using cached setuptools-65.6.3-py3-none-any.whl (1.2 MB)
...
  Attempting uninstall: setuptools
    Found existing installation: setuptools 59.5.0
    Uninstalling setuptools-59.5.0:
      Successfully uninstalled setuptools-59.5.0
...
Successfully installed build-0.9.0 certifi-2022.9.24 charset-normalizer-2.1.1 docutils-0.19 idna-3.4 pep517-0.13.0 pygments-2.13.0 pyroma-4.1 requests-2.28.1 setuptools-65.6.3 trove-classifiers-2022.10.19 urllib3-1.26.13

Here's a passing build with pyroma 4.1 and pinning to old setuptools 59.5.0, but segmentation fault for 3.8 and 3.9 when running tests (3.7 passed):

• https://github.com/hugovk/Pillow/actions/runs/3546858787/jobs/5956383185
• main...hugovk:Pillow:cygwin-pyroma

Here's a failing build with pyroma 4.0 and bumping to latest setuptools:

• https://github.com/hugovk/Pillow/actions/runs/3546920503/jobs/5956469661
• main...hugovk:Pillow:cygwin-pyroma2

Yup, looks like setuptools fun again...

[radarhere]

After looking at #6216 (comment), I've created #6760