[dependabot]: Bump the actions group with 2 updates (#677)

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: mne[bot] <50266005+mne-bot@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -49,7 +49,7 @@ jobs:
         with:
           qt: true
           pyvista: false
-      - uses: mamba-org/setup-micromamba@v2
+      - uses: mamba-org/setup-micromamba@v3
         with:
           environment-file: environment.yml
           environment-name: mne-nirs
@@ -74,5 +74,5 @@ jobs:
           path: ~/mne_data
       - run: ./tools/github_actions_download.sh
       - run: pytest --cov=mne_nirs --cov-report xml -vv -m "not examples" "mne_nirs/"
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v6
         if: success()