Fix issue with xr.core.ops renamed in versions of xarray>=2025.3.0

[jensdebruijn]

Pull Request Checklist:

• This PR addresses an already opened issue (for bug fixes / features)
  • This PR fixes #2113
• Tests for the changes have been added (for bug fixes / features)
  • (If applicable) Documentation has been added / updated (for bug fixes / features)
• CHANGELOG.rst has been updated (with summary of main changes)
  • Link to issue (:issue:number) and pull request (:pull:number) has been added

What kind of change does this PR introduce?

• This PR fixes an issue with an operation not being available in xarray versions later than 2025.3.0

Does this PR introduce a breaking change?

No breaking changes

Other information:

[github-actions]

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[coxipi]

Nice, thanks!

There is also a zenodo.json where you can add your information

[aulemahal]

Ach I can't believe we didn't do that earlier. Thanks a lot!

[Zeitsperre]

Looks like the latest ruff is catching some new errors. Updating in another branch.

[Zeitsperre]

@jensdebruijn I needed to change the branch to one that contained a linting fix to get this to build properly. I hope that's alright.

Bedankt voor de code "changes" en goededag!