Remove pip upgrade step from install docs (#10587)
Remove pip upgrade step from install docs (#10587)

* Remove pip upgrade step

* Trigger CI

* Fix for GPU too

* Trigger CI

TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet,TuSimple/mxnet