CompatHelper: bump compat for OSQP to 0.8, (keep existing compat)

[github-actions]

This pull request changes the compat entry for the OSQP package from 0.3 - 0.7 to 0.3 - 0.7, 0.8.
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 #138 (4a4f194) into master (5185c48) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #138   +/-   ##
=======================================
  Coverage   95.88%   95.88%           
=======================================
  Files          79       79           
  Lines        2382     2382           
=======================================
  Hits         2284     2284           
  Misses         98       98           

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