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

Author: renovate[bot]

.github/workflows/ctest.yml

@@ -95,7 +95,7 @@ jobs:
             api.github.com:443
 
       - name: Download test results
-        uses: actions/download-artifact@634f93cb2916e3fdff6788551b99b062d0335ce0 # v5.0.0
+        uses: actions/download-artifact@018cc2cf5baa6db3ef3c5f8a56943fffe632ef53 # v6.0.0
         with:
           path: test-results