remove spiceypy dependency with updated lunarsky

[aelanman]

Description

The latest version of lunarsky drops the dependency on spiceypy. As a result, the try blocks that catch SPICEUnknownFrameErrors in unit tests can be removed. This also bumps the minimum version of lunarsky.

Motivation and Context

This cleans up code that will no longer be needed.

Build or continuous integration change checklist:

• If required or optional dependencies have changed (including version numbers), I have updated the readme to reflect this.
• If this is a new CI setup, I have added the associated badge to the readme and to references/make_index.py (if appropriate).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.93%. Comparing base (2f7953d) to head (5b1c430).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1671   +/-   ##
=======================================
  Coverage   99.93%   99.93%           
=======================================
  Files          67       67           
  Lines       22848    22848           
=======================================
  Hits        22834    22834           
  Misses         14       14           

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[bhazelton]

Thanks @aelanman! Obviously tests won't pass until the new lunarsky version is released but it's nice to have this ready to go when it is released. There's several other places in the repo where the lunarsky dependency is set, so we'll need to update those as well. Off the top of my head that includes:

• CI conda yamls
• environment.yaml
• readme

Maybe just search the repo to see if there are any more. We also usually put something in the changelog when we increase dependency versions, you can see examples in there from earlier lunarsky version bumps.

[aelanman]

Thanks for the reminder about the changelog @bhazelton ! I've added to that (and for pyuvsim) and updated the README and environment.yaml.