address in1d deprecation

[OriolAbril]

Description

The other two open PRs are failing because the currently numpy nightly has already removed
the deprecated in1d function.

Checklist

• Follows official PR format
• Includes a sample plot to visually illustrate the changes (only for plot-related functions)
• New features are properly documented (with an example if appropriate)?
• Includes new or updated tests to cover the new feature
• Code style correct (follows pylint and black guidelines)
• Changes are listed in changelog

---

📚 Documentation preview 📚: https://arviz--2493.org.readthedocs.build/en/2493/

[codecov]

Codecov Report

❌ Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 86.83%. Comparing base (495f709) to head (5b02a73).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
arviz/plots/bpvplot.py	0.00%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (50.00%) is below the target coverage (75.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2493      +/-   ##
==========================================
+ Coverage   86.82%   86.83%   +0.01%     
==========================================
  Files         124      124              
  Lines       13020    13020              
==========================================
+ Hits        11304    11306       +2     
+ Misses       1716     1714       -2     

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