fix artifact upload

Author: mustard-mh

.github/workflows/build.yml

@@ -69,7 +69,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: [generate_toolchain, generate_musl_toolchain]
     steps:
-      - uses: actions/download-artifact@v3
+      - uses: actions/download-artifact@v4
         with:
           path: artifacts/