Bump actions/upload-artifact from 5 to 6

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>

Author: dependabot[bot]

.github/workflows/build-deploy.yml

@@ -56,7 +56,7 @@ jobs:
         working-directory: docs
       # Save the generated documentation as an artifact in Github
       - name: Upload documentation
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: python-doc-package
           path: docs/_build/
@@ -87,7 +87,7 @@ jobs:
       - name: Build Python package
         run: python -m build
       - name: Upload Python package
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: python-package
           path: dist/