Fixing a further coords attrs fail.

[lpilz]

Change Summary

Fix based on https://github.com/xarray-contrib/xwrf/issues/104#issuecomment-1251644588

Related issue number

Related to #104

Checklist

• [x] Unit tests for the changes exist
• [x] Tests pass on CI
• [ ] Documentation reflects the changes where applicable

[lpilz]

Auto-merging this so for expediency's sake