Release v5.1.6

[jhkennedy]

Developer checklist

• [x] Assigned a reviewer
• [x] 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) Added/updated documentation for these changes
• [ ] (If applicable) Added/updated tests for these changes

[jhkennedy]

Watermap job running in hyp3-test: https://hyp3-test-api.asf.alaska.edu/jobs/193502e9-738e-4537-9193-4463525e5e86 Golden RTC: https://github.com/ASFHyP3/hyp3-testing/runs/5412603401?check_suite_focus=true Golden InSAR: https://github.com/ASFHyP3/hyp3-testing/runs/5412606363?check_suite_focus=true

[jhkennedy]

Watermap job finished successfully! RTC Golden Passed! Golden InSAR failed but just in the normal unwrapped phase way...

Pretty sure we're ready to :shipit: