Update gen_requirements.py with new onnx things  (#9541)
Update gen_requirements.py with new onnx things  (#9541)

* adds onnxoptimizer to gen_requirements.py
Laurawly/tvm-1,Laurawly/tvm-1,dmlc/tvm,dmlc/tvm,dmlc/tvm,dmlc/tvm,Laurawly/tvm-1,dmlc/tvm,Laurawly/tvm-1,dmlc/tvm,dmlc/tvm,Laurawly/tvm-1,Laurawly/tvm-1,Laurawly/tvm-1,Laurawly/tvm-1,dmlc/tvm,Laurawly/tvm-1,dmlc/tvm,Laurawly/tvm-1