ci: Update codecov action

Author: perlpunk

.github/workflows/linux.yaml

@@ -89,7 +89,7 @@ jobs:
 
         cover -report codecovbash
     - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v6
       with:
         file: ./cover_db/codecov.json
         fail_ci_if_error: true