CompatHelper: bump compat for Compat to 4, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the Compat package from 3.33 to 3.33, 4.
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]

Codecov Report

Merging #163 (69eceb5) into master (2cb4068) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #163   +/-   ##
=======================================
  Coverage   91.91%   91.91%           
=======================================
  Files          12       12           
  Lines        1225     1225           
=======================================
  Hits         1126     1126           
  Misses         99       99           

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[visr]

Would be nice to have this. Tests pass, also checked locally. The potentially breaking changes are documented in JuliaLang/Compat.jl#775, but none seem to apply for this package.

[rofinn]

Sorry, just forgot about this.