Make Cowboy depend on 0.6.0 instead of master
Make Cowboy depend on 0.6.0 instead of master

I have breaking changes planned after 0.6.0 and I wouldn't want
this benchmark to stop working considering how important it is. :)
beni55/wsdemo,beni55/wsdemo,beni55/wsdemo,ericmoritz/wsdemo,ericmoritz/wsdemo,beni55/wsdemo,beni55/wsdemo,ericmoritz/wsdemo,ericmoritz/wsdemo,ericmoritz/wsdemo,beni55/wsdemo,ericmoritz/wsdemo,ericmoritz/wsdemo,ericmoritz/wsdemo,beni55/wsdemo