Use Forgejo-compatible artifact actions

.forgejo/workflows/publish-package-repositories.yml

@@ -133,7 +133,7 @@ jobs:
           nix develop .#ci -c Scripts/package/build-repositories.sh all
 
       - name: Upload Repository Artifact
-        uses: https://code.forgejo.org/actions/upload-artifact@v4
+        uses: https://code.forgejo.org/actions/upload-artifact@v3
         with:
           name: burrow-package-repositories-${{ github.event.inputs.channel || 'stable' }}-${{ github.event.inputs.build_number || github.sha }}
           path: dist/builds/${{ github.event.inputs.build_number || github.sha }}/repositories/**