Bump codecov/codecov-action from 5 to 6 (#1584)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 5 to 6.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v5...v6)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/tests.yaml

@@ -200,4 +200,4 @@ jobs:
           micromamba run -n test sphinx-build -b html docs/ docs/_build/
           micromamba run -n test sphinx-build -b man docs/ docs/_build/
 
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v6