CompatHelper: add new compat entry for MixedModelsSmallSample at version 0.1 for package docs, (keep existing compat)

[github-actions]

This pull request sets the compat entry for the MixedModelsSmallSample package to 0.1 for package docs.
This keeps the compat entries for earlier versions.

Note: I have not tested your package with this new compat entry.
It is your responsibility to make sure that your package tests pass before you merge this pull request.
Note: Consider registering a new release of your package immediately after merging this PR, as downstream packages may depend on this for tests to pass.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.42%. Comparing base (a806546) to head (845327c).

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #90      +/-   ##
==========================================
- Coverage   89.31%   88.42%   -0.89%     
==========================================
  Files           9        8       -1     
  Lines         290      285       -5     
==========================================
- Hits          259      252       -7     
- Misses         31       33       +2     

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