chore(deps): update actions/download-artifact action to v6

Signed-off-by: bootc-bot[bot] <225049296+bootc-bot[bot]@users.noreply.github.com>

Author: bootc-bot[bot]

.github/workflows/ci.yml

@@ -182,7 +182,7 @@ jobs:
           fi
 
       - name: Download package artifacts
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: packages-${{ matrix.test_os }}
           path: target/packages/