Replace the old Rocky cycle signing key with Stein
Replace the old Rocky cycle signing key with Stein

This is a zuul-encrypted export of the signing subkey for the Stein
release cycle: 0x27023b1ffccd8e3ae9a5ce95d943d5d270273ada

Change-Id: Id8f608eea622d2529a3367de84a255a3a7fc95e8

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