Build(deps): Bump the actions group with 2 updates

Bumps the actions group with 2 updates: [mamba-org/setup-micromamba](https://github.com/mamba-org/setup-micromamba) and [codecov/codecov-action](https://github.com/codecov/codecov-action).


Updates `mamba-org/setup-micromamba` from 2 to 3
- [Release notes](https://github.com/mamba-org/setup-micromamba/releases)
- [Commits](mamba-org/setup-micromamba@v2...v3)

Updates `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: mamba-org/setup-micromamba
  dependency-version: '3'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: codecov/codecov-action
  dependency-version: '6'
  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/tests.yml

@@ -38,7 +38,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - uses: pyvista/setup-headless-display-action@main
-      - uses: mamba-org/setup-micromamba@v2
+      - uses: mamba-org/setup-micromamba@v3
         with:
           environment-file: environment.yml
       #
@@ -49,7 +49,7 @@ jobs:
       - run: python -c "from mayavi import mlab; mlab.test_plot3d()"
       - run: python -c "import mne; mne.datasets.testing.data_path(verbose=True)"
       - run: pytest --tb=short --cov=mne_kit_gui --cov-report=xml --cov-report=html -vvv mne_kit_gui
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v6
         with:
           token: ebcd818a-7a71-470d-b667-7cd9c3003c7d
         if: success() || failure()