Bump actions/upload-artifact from 5 to 6 (#20)

Bumps [actions/upload-artifact](https://github.com/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
...

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/build.yaml

@@ -46,7 +46,7 @@ jobs:
           python -c "import lpath.lpath" &&
           echo "All done with import tests!"
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: artifact-wheels
           path: dist/*.whl
@@ -81,7 +81,7 @@ jobs:
           python -c "import lpath.lpath" &&
           echo "All done with import tests!"
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: artifact-sdist
           path: dist/*.tar.gz