ci: change codecov GHA version to v3

[gruebel]

This PR

• I'm not sure why chore(deps): update codecov/codecov-action digest to c256d56 - autoclosed #226 fails the whole time, but this will remove the need to bump the version every couple of weeks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (1722848) 93.84% compared to head (3708d18) 93.84%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #259   +/-   ##
=======================================
  Coverage   93.84%   93.84%           
=======================================
  Files          16       16           
  Lines         439      439           
=======================================
  Hits          412      412           
  Misses         27       27           

Flag	Coverage Δ
unittests	93.84% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.