Pin xarray to 2025.06.0

[maxrjones]

We currently only support one version of xarray, see https://github.com/zarr-developers/VirtualiZarr/actions/runs/16381686949/job/46294326109?pr=703 for incompatibility with earlier versions and #688 for compatibility with future versions

• Closes #xxxx
• Tests added
• Tests passing
• Full type hint coverage
• Changes are documented in docs/releases.rst
• New functions/methods are listed in api.rst
• New functionality has documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.65%. Comparing base (9611c4f) to head (37a4044).
⚠️ Report is 49 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #705   +/-   ##
=======================================
  Coverage   88.65%   88.65%           
=======================================
  Files          34       34           
  Lines        1833     1833           
=======================================
  Hits         1625     1625           
  Misses        208      208           

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[maxrjones]

Upstream failure will be fixed by fsspec/kerchunk#570.