Release 0.6.0

[AndrewPlayer3]

Before merge

• [x] Merge https://github.com/ASFHyP3/mkdocs-asf-theme/pull/44
• [x] Merge https://github.com/ASFHyP3/hyp3-docs/pull/374

After merge

• [x] Verify website still renders and functions as expected

[github-actions[bot]]

Developer checklist

• [ ] Indicated the level of changes to this package by affixing one of these labels:
  • major -- Major changes to the API that may break current workflows
  • minor -- Minor changes to the API that do not break current workflows
  • patch -- Patches and bugfixes for the current version that do not break current workflows
  • bumpless -- Changes to documentation, CI/CD pipelines, etc. that don't affect the software's version
• [ ] (If applicable) Updated the dependencies and indicated any downstream changes that are required
• [ ] Added/updated documentation for these changes
• [ ] Added/updated tests for these changes

Reviewer checklist

• [ ] Have all dependencies been updated?
• [ ] Is the level of changes labeled appropriately?
• [ ] Are all the changes described appropriately in CHANGELOG.md?
• [ ] Has the documentation been adequately updated?
• [ ] Are the tests adequate?

[asjohnston-asf]

I'm happy with all of the DEM-related changes in this PR. I'll let @jhkennedy and @jtherrmann handle approval when they're happy with the theme-related changes.