fix: Fix compatibility with packaging 26

[frostming]

Fixes #3729

Signed-off-by: Frost Ming me@frostming.com

Pull Request Checklist

• A news fragment is added in news/ describing what is new.
• Test cases added for changed code.

Describe what you have changed in this PR.

[codecov]

Codecov Report

❌ Patch coverage is 55.55556% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.88%. Comparing base (956ff17) to head (631d7ae).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
src/pdm/utils.py	33.33%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3730      +/-   ##
==========================================
- Coverage   85.93%   85.88%   -0.05%     
==========================================
  Files         118      118              
  Lines       12366    12372       +6     
  Branches     2058     2060       +2     
==========================================
- Hits        10627    10626       -1     
- Misses       1168     1173       +5     
- Partials      571      573       +2     

Flag	Coverage Δ
unittests	85.74% <55.55%> (-0.05%)	⬇️

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