Bump codecov/codecov-action from 4 to 5 in the actions group

Bumps the actions group with 1 update: [codecov/codecov-action](https://github.com/codecov/codecov-action).


Updates `codecov/codecov-action` from 4 to 5
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v4...v5)

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

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

.github/workflows/tests.yml

@@ -128,7 +128,7 @@ jobs:
           path: ~/mne_data
       - run: ./tools/github_actions_download.sh
       - run: ./tools/github_actions_test.sh
-      - uses: codecov/codecov-action@v4
+      - uses: codecov/codecov-action@v5
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
         if: always()