add release announcement jobs to the pre-release queue
add release announcement jobs to the pre-release queue

We are adding the ability to automatically announce release candidates,
so we need to trigger the announce-release job for pre-release versions
like x.y.z.0rc1. The announce.sh script will ignore alpha and beta
versions.

Change-Id: Id241ea1d925d6653bccba9460c1a307db11f97ea
Depends-On: Iba630343d3041a341ad430996f50d9262da8a217
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

openstack-infra/project-config,openstack-infra/project-config