fix teams dep on botbuilder-core (#1871)
fix teams dep on botbuilder-core (#1871)

pip refuses to install deps that are not hosted on pypi. oops. But botbuilder loosened their deps so that shouldnot be a problem any more with botbuilder-core 4.13+
opsdroid/opsdroid,jacobtomlinson/opsdroid,FabioRosado/opsdroid