Plan release 4.13.1

[JelleZijlstra]

We had a few bugfixes after the latest release (thanks @Daraan!), so let's put out a bugfix release for them.

Please post here if you think anything else should go in the bugfix release, otherwise I'll try to do it later this week.

We should also hopefully do a new feature release soonish with PEP 764 support, Python 3.14 updates (#564), anything the SC wants me to change in PEP 749, and dropping 3.8 (#568).