Add date to 0.23.1 release notes

[lagru]

Description

Just making it consistent with the other notes and adding a note of the task to our release instructions.

Checklist

• A descriptive but concise pull request title
• Docstrings for all functions
• Unit tests
• A gallery example in ./doc/examples for new features
• Contribution guide is followed

Release note

We use changelist to
compile each pull request into an item of the release notes. Please refer to
the instructions
and past release notes
for guidance and examples.

...

[lagru]

Can't really explain why the version bumb earlier is happily using np.infty without a deprecation warning while the doc build for this PR is failing because of it only 16 hours later.

Only dependency that changed between jobs is idna, from 3.6 to 3.7.

Fix should be simple though.

[lagru]

Only dependency that changed between jobs is idna, from 3.6 to 3.7.

Ah, that statement is wrong. After the tests, before installing the docs there's another call to pip install which pulled in NumPy 1.26.4 previously and is now using NumPy 2.0.0rc1. I think that's because of Pandas.

Addressed in #7386.