chore: update xarray requirement from <0.19 to <2022.10

[dependabot]

Updates the requirements on xarray to permit the latest version.

Changelog

Sourced from xarray's changelog.

How to issue an xarray release in 16 easy steps

Time required: about an hour.

These instructions assume that upstream refers to the main repository:

$ git remote -v
{...}
upstream        https://github.com/pydata/xarray (fetch)
upstream        https://github.com/pydata/xarray (push)

1. Ensure your main branch is synced to upstream:

   git switch main
   git pull upstream main

2. Add a list of contributors with:

   git log "$(git tag --sort=v:refname | tail -1).." --format=%aN | sort -u | perl -pe 's/\n/$1, /'

   This will return the number of contributors:

   git log "$(git tag --sort=v:refname | tail -1).." --format=%aN | sort -u | wc -l

3. Write a release summary: ~50 words describing the high level features. This will be used in the release emails, tweets, GitHub release notes, etc.
4. Look over whats-new.rst and the docs. Make sure "What's New" is complete (check the date!) and add the release summary at the top. Things to watch out for:
   • Important new features should be highlighted towards the top.
   • Function/method references should include links to the API docs.
   • Sometimes notes get added in the wrong section of whats-new, typically due to a bad merge. Check for these before a release by using git diff, e.g., git diff v{YYYY.MM.X-1} whats-new.rst where {YYYY.MM.X-1} is the previous release.
5. Open a PR with the release summary and whatsnew changes; in particular the release headline should get feedback from the team on what's important to include.
6. After merging, again ensure your main branch is synced to upstream:

   git pull upstream main

7. If you have any doubts, run the full test suite one final time!

   pytest

8. Check that the ReadTheDocs build is passing on the main branch.

... (truncated)

Commits

• 208e588 2022.09.0 release summary (#7107)
• 2fe7875 Fix deepcopy of Variables and DataArrays (#7089)
• 6b2fdab Added test_deepcopy_nested_attrs() (#2835). (#7086)
• 0b0b8f6 move coverage to pyproject.toml and exclude typechecking things (#7102)
• 2c43663 Fix bug with netcdf when units attribute is not a string (#7085)
• 5ba830d Add typing to FacetGrid (#7087)
• 513ee34 Fix Dataset.assign_coords overwriting multi-index (#7101)
• e2c29f6 Fix utils.get_axis with kwargs (#7080)
• 226c23b Add Ellipsis typehint to reductions (#7048)
• e678a1d Add set_xindex and drop_indexes methods (#6971)
• Additional commits viewable in compare view

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[dependabot]

Superseded by #66.