Bump actions/upload-artifact from 5 to 6 (#326)

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -40,7 +40,7 @@ jobs:
       continue-on-error: true
     - name: Pack
       run: dotnet pack --output ./artifacts --configuration Release --no-build
-    - uses: actions/upload-artifact@v5
+    - uses: actions/upload-artifact@v6
       with:
         name: artifacts
         path: ./artifacts