refactor(deps): bump actions/upload-artifact from 5 to 6 (#20)

Author: dependabot[bot]

.github/workflows/buildrelease.yml

@@ -18,7 +18,7 @@ jobs:
         shell: bash
 
       - name: Upload tarball
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: python-tarball
           path: Python-${{ github.ref_name }}.tgz