chore(deps): update codecov/codecov-action action to v6

Author: renovate[bot]

.github/workflows/unit_tests.yml

@@ -70,4 +70,4 @@ jobs:
       - name: Upload coverage
         env:
           CODECOV_TOKEN: ${{secrets.CODECOV_TOKEN}}
-        uses: codecov/codecov-action@v2
+        uses: codecov/codecov-action@v6