Update actions/download-artifact action from v5 to v6 (major v6)

Author: renovate[bot]

.github/workflows/release.yml

@@ -82,7 +82,7 @@ jobs:
     steps:
     - name: Checkout repo
       uses: actions/checkout@v5
-    - uses: actions/download-artifact@v5
+    - uses: actions/download-artifact@v6
       with:
         merge-multiple: true
         path: artifacts