Bump actions/upload-artifact from 5 to 6 in the github-actions group

Bumps the github-actions group with 1 update: [actions/upload-artifact](https://github.com/actions/upload-artifact).


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

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -94,7 +94,7 @@ jobs:
         ls -l dist
         twine check dist/*
     - name: Store greenlet wheel
-      uses: actions/upload-artifact@v5
+      uses: actions/upload-artifact@v6
       with:
         name: greenlet-${{ runner.os }}-${{ matrix.python-version }}.whl
         path: dist/*whl
@@ -220,7 +220,7 @@ jobs:
           DOCKER_IMAGE: quay.io/pypa/${{ matrix.image }}
         run: bash ./make-manylinux
       - name: Store greenlet wheels
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           path: wheelhouse/*whl
           name: ${{ matrix.image }}_wheels.zip