Add submodule update script used by gocd
Add submodule update script used by gocd

[#109618622]

Signed-off-by: Andrew Bruce <9f3496284b4c2f106c6fd659e0e410c1210cf477@pivotal.io>

pivotal-cf/cf-rabbitmq-release,pivotal-cf/cf-rabbitmq-release,pivotal-cf/cf-rabbitmq-release,pivotal-cf/cf-rabbitmq-release