Limit the version of vllm to avoid dockers build failures. (#1183)

Signed-off-by: ZePan110 <ze.pan@intel.com>

.github/workflows/_example-workflow.yml

@@ -75,7 +75,7 @@ jobs:
           docker_compose_path=${{ github.workspace }}/${{ inputs.example }}/docker_image_build/build.yaml
           if [[ $(grep -c "vllm:" ${docker_compose_path}) != 0 ]]; then
               git clone https://github.com/vllm-project/vllm.git
-              cd vllm && git rev-parse HEAD && cd ../
+              cd vllm && git checkout 446c780 && cd ../
           fi
           if [[ $(grep -c "vllm-gaudi:" ${docker_compose_path}) != 0 ]]; then
                git clone https://github.com/HabanaAI/vllm-fork.git