CompatHelper: bump compat for "StatsFuns" to "0.9"

[github-actions]

This pull request changes the compat entry for the StatsFuns package from 0.8.0 to 0.8.0, 0.9.

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.

[codecov-io]

Codecov Report

Merging #37 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #37   +/-   ##
=======================================
  Coverage   99.31%   99.31%           
=======================================
  Files          12       12           
  Lines         881      881           
=======================================
  Hits          875      875           
  Misses          6        6

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