Update codecov/codecov-action action to v6

Signed-off-by: red-hat-konflux <126015336+red-hat-konflux[bot]@users.noreply.github.com>

Author: red-hat-konflux[bot]

.github/workflows/unittests.yml

@@ -15,7 +15,7 @@ jobs:
     - uses: actions/checkout@v6
     - name: Run unit tests
       run: docker compose -f docker-compose.test.yml up --build --exit-code-from test
-    - uses: codecov/codecov-action@v4
+    - uses: codecov/codecov-action@v6
       with:
         files: ./coverage.txt
         flags: unittests