build(deps): bump actions/upload-artifact from 6 to 7

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/v6...v7)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/python-wheels.yml

@@ -27,7 +27,7 @@ jobs:
         with:
           package-dir: python
 
-      - uses: actions/upload-artifact@v6
+      - uses: actions/upload-artifact@v7
         with:
           name: opendht-wheels-${{ matrix.os }}
           path: ./wheelhouse/*.whl
@@ -86,7 +86,7 @@ jobs:
           pipx run cibuildwheel python
         shell: pwsh
 
-      - uses: actions/upload-artifact@v6
+      - uses: actions/upload-artifact@v7
         with:
           name: opendht-wheels-win_amd64
           path: ./build/wheelhouse/*.whl