MAINT: Add warning filter for np.long

[mtsokol]

Hi!
This is a one-line follow-up PR after #55369.
Downstream libs that use nightly pandas and numpy will see a warning without it (there was a similar fix for scipy: scipy/scipy#19341).

[pllim]

Hello (again) and thanks for this PR. I am seeing the warning but this time from pandas instead of scipy.

pandas/pandas/compat/numpy/__init__.py

Line 29 in 06cdcc0

np_long = np.long # type: ignore[attr-defined]

Example log: https://github.com/spacetelescope/jdaviz/actions/runs/6407816486/job/17396675526?pr=2492

[mroeschke]

Great thanks @mtsokol

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 2.1.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 eb6317a3cf45dfeb76f81655310604de029ad596

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #55397: MAINT: Add warning filter for `np.long`'

4. Push to a named branch:

git push YOURFORK 2.1.x:auto-backport-of-pr-55397-on-2.1.x

5. Create a PR against branch 2.1.x, I would have named this PR:

"Backport PR #55397 on branch 2.1.x (MAINT: Add warning filter for np.long)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.

[mroeschke]

@meeseeksdev backport 2.1.x