Update setup.py
Update setup.py

msbuild fix for vs2017 - do not specify msbuild version
AlexCatarino/pythonnet,yagweb/pythonnet,AlexCatarino/pythonnet,pythonnet/pythonnet,QuantConnect/pythonnet,yagweb/pythonnet,pythonnet/pythonnet,QuantConnect/pythonnet,pythonnet/pythonnet,yagweb/pythonnet,AlexCatarino/pythonnet,yagweb/pythonnet,QuantConnect/pythonnet,AlexCatarino/pythonnet