Bump actions/upload-artifact from 6 to 7 (#6906)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 6 to 7.

- vLLM version: v0.16.0
- vLLM main:
15d76f74e2

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.github/workflows/_e2e_nightly_multi_node.yaml

@@ -255,7 +255,7 @@ jobs:
 
         - name: Upload logs
           if: always()
-          uses: actions/upload-artifact@v6
+          uses: actions/upload-artifact@v7
           with:
             name: ${{ inputs.config_file_path }}-pod-logs
             path: /tmp/vllm*_logs.txt