ci: fix codecov

Signed-off-by: David Wallace <mypydavid@proton.me>

Author: David Wallace

.github/workflows/build-test-codecov.yml

@@ -46,7 +46,7 @@ jobs:
       - name: Upload Coverage to Codecov
         uses: codecov/codecov-action@v5
         with:
-          file: ./coverage.xml
+          files: ./coverage.xml
           flags: unittests
           name: codecov-umbrella
           fail_ci_if_error: true