Add Codecov token to test workflow

Sets the CODECOV_TOKEN secret in the Codecov upload step to ensure proper authentication during coverage reporting.

Author: douden

.github/workflows/tests.yml

@@ -48,6 +48,7 @@ jobs:
         flags: pytests
         file: ./coverage.xml
         fail_ci_if_error: false # uploading coverage should not fail the tests
+        token: ${{ secrets.CODECOV_TOKEN }}
 
   publish: