v0.7.0

What's Changed

• 🚀🚀🚀 Grid ufunc refactor by @TomNicholas in https://github.com/xgcm/xgcm/pull/479🤘🤘🤘
• Switch to pangeo book theme by @jbusecke in #482
• Correction of the Grid.init docstring by @rcaneill in #369
• Update black version in pre-commit by @jbusecke in #472
• Increase CI time limit by @jbusecke in #473
• Add CITATION.cff by @jbusecke in #450
• Include submodules in RTD by @jbusecke in #477

Full Changelog: v0.6.1...v0.7.0