[dependabot]: Bump the actions group with 2 updates

Bumps the actions group with 2 updates: [actions/upload-artifact](https://github.com/actions/upload-artifact) and [actions/download-artifact](https://github.com/actions/download-artifact).


Updates `actions/upload-artifact` from 5 to 6
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

Updates `actions/download-artifact` from 6 to 7
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v6...v7)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: actions/download-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/release.yml

@@ -28,7 +28,7 @@ jobs:
           pip install build twine
       - run: python -m build --sdist --wheel
       - run: twine check --strict dist/*
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: dist
           path: dist
@@ -43,7 +43,7 @@ jobs:
       name: pypi
       url: https://pypi.org/p/mne-features
     steps:
-      - uses: actions/download-artifact@v6
+      - uses: actions/download-artifact@v7
         with:
           name: dist
           path: dist