Update instructions for getting gas
Update instructions for getting gas

The repo has moved and instructions changed.

Signed-off-by: Justin Cormack <af64ee19f04db9509cb02b0e470e11e5402ef9b3@docker.com>

endophage/notary,docker/notary,docker/notary,endophage/notary,jfrazelle/notary,jfrazelle/notary,HuKeping/notary,HuKeping/notary,docker/notary,endophage/notary,jfrazelle/notary,HuKeping/notary