Switch concourse resource to master branch
Switch concourse resource to master branch

[#73636468](https://www.pivotaltracker.com/story/show/73636468)

Signed-off-by: Aaron Hurley <6c541e38cb40b4360b80e64c308405691f38e38a@pivotal.io>

cloudfoundry-incubator/bosh-vsphere-cpi-release,nimbus-cloud/bosh-vsphere-cpi-release,wcamarao/bosh-vsphere-cpi-release,cloudfoundry-incubator/bosh-vsphere-cpi-release,rexxar-liang/bosh-vsphere-cpi-release,rexxar-liang/bosh-vsphere-cpi-release,cloudfoundry-incubator/bosh-vsphere-cpi-release,cloudfoundry-incubator/bosh-vsphere-cpi-release,rexxar-liang/bosh-vsphere-cpi-release,wcamarao/bosh-vsphere-cpi-release,nimbus-cloud/bosh-vsphere-cpi-release,nimbus-cloud/bosh-vsphere-cpi-release,wcamarao/bosh-vsphere-cpi-release,cloudfoundry-incubator/bosh-vsphere-cpi-release