ignore addressed attrs deprecation warning in oldestdeps

[braingram]

The newest version of attrs includes a deprecation warning for a feature used in asdf:
https://github.com/python-attrs/attrs/releases/tag/24.1.0
This has been addressed:
asdf-format/asdf#1815
and released in asdf 3.4.0
https://github.com/asdf-format/asdf/releases/tag/3.4.0

However the oldestdeps job here will not pick up the change until the minimum asdf version is 3.4.0. This is because the oldest deps job only installs the oldest versions of direct dependencies (like asdf) and will install the newest version of indirect deps (like attrs).

This PR adds a warning filter to ignore the warning from attrs.

Checklist

• Added entry in CHANGES.rst under the corresponding subsection
• updated relevant tests
• updated relevant documentation
• Passed romancal regression testing on Jenkins / PLWishMaster. Link: https://plwishmaster.stsci.edu:8081/job/RT/job/romancal/XXX/

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.66%. Comparing base (087a60d) to head (f167029).
Report is 63 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #371      +/-   ##
==========================================
+ Coverage   97.56%   97.66%   +0.10%     
==========================================
  Files          30       36       +6     
  Lines        2788     3335     +547     
==========================================
+ Hits         2720     3257     +537     
- Misses         68       78      +10     

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[PaulHuwe]

LGTM