Add pushMerge access to refstack-release group
Add pushMerge access to refstack-release group

This will allow feature branches to be merged with master or
vice versa.

Change-Id: I5c62e0281b22a96a91dcde0611f398d918d0f69c

openstack-infra/project-config,Tesora/tesora-project-config,Tesora/tesora-project-config,dongwenjuan/project-config,openstack-infra/project-config,dongwenjuan/project-config