Bump codecov/codecov-action from 3 to 4 in /.github/workflows

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 3 to 4.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v3...v4)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Diff for: .github/workflows/unit-tests.yml

@@ -49,7 +49,7 @@ jobs:
           echo "CODECOV_TOKEN=$CODECOV_TOKEN" >> "$GITHUB_ENV"
 
       - name: Upload coverage report to Codecov
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v4
         with:
           file: "${{ env.COVERAGE_DATA_PATH }}"
           fail_ci_if_error: true