CompatHelper: bump compat for "ArgCheck" to "2.0"

[github-actions]

This pull request changes the compat entry for the ArgCheck package from ^1 to ^1, 2.0.

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

@@           Coverage Diff           @@
##           master     #216   +/-   ##
=======================================
  Coverage   86.36%   86.36%           
=======================================
  Files           9        9           
  Lines         616      616           
=======================================
  Hits          532      532           
  Misses         84       84

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