Update to CPM v0.38.5

[trxcllnt]

Description

Update to CPM v0.38.5.

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.
• The cmake-format.json is up to date with these changes.
• I have added new files under rapids-cmake/
  • I have added include guards (include_guard(GLOBAL))
  • I have added the associated docs/ rst file and update the api.rst

[robertmaynard]

Unless we absolutely need this for 23.10 lets merge this first for 23.12 so we have lots of time to find and fix issues

[trxcllnt]

@robertmaynard CPM v0.38 is the one that added support for add_subdirectory(... [SYSTEM]), which is the feature that motivated this particular PR. Is upgrading CPM really that risky?

[robertmaynard]

I didn't know if this was a simple version bump to keep up to date, or for new features.
Since we have a need for add_subdirectory(SYSTEM) I am good with adding this to 23.10

[robertmaynard]

/merge