Bump codecov/codecov-action from 5 to 6 (#234)

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

Author: dependabot[bot]

.github/workflows/pytest.yaml

@@ -37,7 +37,7 @@ jobs:
       - run: uv sync -q --no-default-groups --group test
       - run: template sys-info --developer
       - run: pytest tests --cov=template --cov-report=xml --cov-config=pyproject.toml
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v6
         if: ${{ github.repository == 'mscheltienne/template-python' }}
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
@@ -64,7 +64,7 @@ jobs:
           uv pip install -q --upgrade --prerelease allow --only-binary :all: -i https://pypi.anaconda.org/scientific-python-nightly-wheels/simple numpy
       - run: template sys-info --developer
       - run: pytest tests --cov=template --cov-report=xml --cov-config=pyproject.toml
-      - uses: codecov/codecov-action@v5
+      - uses: codecov/codecov-action@v6
         if: ${{ github.repository == 'mscheltienne/template-python' }}
         with:
           token: ${{ secrets.CODECOV_TOKEN }}