added supported python versions to install instructions
added supported python versions to install instructions

yangchaogit/locust,rohitgup14/locust,Diogo-Costa/locust,scalp42/locust,dmoliveira/locust,pmdarrow/locust,yangchaogit/locust,jaume-pinyol/locust,kyroskoh/locust,mbeacom/locust,minhoryang/locust,bugsduggan/locust,leo23/locust,TZer0/locust,jacobgardner/locust,minhoryang/locust,ismail-s/locust,locustio/locust,minhoryang/locust,cgoldberg/locust,jacobgardner/locust,timaakulich/locust,leo23/locust,harrisonfeng/locust,pmdarrow/locust,santiavenda2/locust,fengshao0907/locust,harrisonfeng/locust,fordhurley/locust,leo23/locust,harrisonfeng/locust,liubq919/locust,TZer0/locust,yangchaogit/locust,santiavenda2/locust,armersong/locust,moongtaeng/locust,Diogo-Costa/locust,rackerlabs/locust,fengshao0907/locust,fengshao0907/locust,wndhydrnt/locust,moongtaeng/locust,rackerlabs/locust,pmdarrow/locust,doctoryes/locust,ismail-s/locust,timaakulich/locust,donglei/locust,fengshao0907/locust,donglei/locust,rohitgup14/locust,wndhydrnt/locust,Diogo-Costa/locust,jaume-pinyol/locust,bugsduggan/locust,kentzzhang/locust,noif/locust,dmoliveira/locust,nagyistoce/locust,Diogo-Costa/locust,yangchaogit/locust,lixar/locust,pan1cz/locust,doctoryes/locust,donglei/locust,kyroskoh/locust,ismail-s/locust,kyroskoh/locust,lixar/locust,liubq919/locust,kentzzhang/locust,leo23/locust,pan1cz/locust,normanb/locust,normanb/locust,cgoldberg/locust,kentzzhang/locust,noif/locust,donglei/locust,cgoldberg/locust,lixar/locust,locustio/locust,wndhydrnt/locust,fordhurley/locust,rohitgup14/locust,armersong/locust,mbeacom/locust,dmoliveira/locust,TZer0/locust,mbeacom/locust,doctoryes/locust,normanb/locust,nagyistoce/locust,rohitgup14/locust,mbeacom/locust,scalp42/locust,heyman/locust,noif/locust,moongtaeng/locust,dmoliveira/locust,scalp42/locust,liubq919/locust,santiavenda2/locust,armersong/locust,doctoryes/locust,moongtaeng/locust,lixar/locust,timaakulich/locust,nagyistoce/locust,kentzzhang/locust,noif/locust,armersong/locust,bugsduggan/locust,jacobgardner/locust,jaume-pinyol/locust,fordhurley/locust,locustio/locust,locustio/locust,wndhydrnt/locust,rackerlabs/locust,pan1cz/locust