Use external workers to allow running in GCP
Use external workers to allow running in GCP

This is compatible with concourse 3 and 2.7.3 but the pipeline at this
commit can only be run on the gpdb concourse deployment in GCP (it is
the deployment with the external workers).

Signed-off-by: Divya Bhargov <7b80d57abdba07f5e9cc370edef1f7da6a49b81f@pivotal.io>
Signed-off-by: Jim Doty <1edafe41f7177ae695a4a212e0a903db6d46d401@pivotal.io>
Signed-off-by: Alexandra Wang <2104ed7b77de63c11d65f08ed993b286192143d2@pivotal.io>

50wu/gpdb,adam8157/gpdb,adam8157/gpdb,greenplum-db/gpdb,edespino/gpdb,ashwinstar/gpdb,Chibin/gpdb,xinzweb/gpdb,lisakowen/gpdb,edespino/gpdb,jmcatamney/gpdb,lisakowen/gpdb,adam8157/gpdb,lisakowen/gpdb,50wu/gpdb,jmcatamney/gpdb,edespino/gpdb,greenplum-db/gpdb,lisakowen/gpdb,xinzweb/gpdb,50wu/gpdb,yuanzhao/gpdb,xinzweb/gpdb,Chibin/gpdb,yuanzhao/gpdb,edespino/gpdb,50wu/gpdb,edespino/gpdb,Chibin/gpdb,edespino/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,50wu/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,lisakowen/gpdb,adam8157/gpdb,adam8157/gpdb,edespino/gpdb,Chibin/gpdb,lisakowen/gpdb,yuanzhao/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,edespino/gpdb,Chibin/gpdb,50wu/gpdb,jmcatamney/gpdb,yuanzhao/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,lisakowen/gpdb,xinzweb/gpdb,greenplum-db/gpdb,Chibin/gpdb,adam8157/gpdb,yuanzhao/gpdb,xinzweb/gpdb,Chibin/gpdb,edespino/gpdb,greenplum-db/gpdb,xinzweb/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,Chibin/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,xinzweb/gpdb,yuanzhao/gpdb,adam8157/gpdb,50wu/gpdb,ashwinstar/gpdb,adam8157/gpdb,Chibin/gpdb,lisakowen/gpdb,yuanzhao/gpdb,50wu/gpdb,Chibin/gpdb,yuanzhao/gpdb,jmcatamney/gpdb,edespino/gpdb,xinzweb/gpdb