sre_constants is deprecated

[oliver-sanders]

The sre_constants module is now deprecated at Python 3.11 for removal in Python 3.13.

https://docs.python.org/3/whatsnew/3.11.html#modules

[MetRonnie]

https://github.com/metomi/isodatetime/blob/658b31e6905896e5df183da561d8d21005960771/metomi/isodatetime/parsers.py#L344-L347

Probably can just replace with Exception. The line in question is showing as not covered by tests so could do with adding a few while we're at it

[ColemanTom]

Just to note two things

1. sre_constants is still in python 3.13, which does go against their usual approach, but anyway, its still there
2. You maybe should pin the max python version in the conda feedstock to be <3.14 as a safety feature.

[MetRonnie]

• (Still open: https://github.com/python/cpython/issues/105456)