Fix post migration deployment, setting it prior to the workers run

Bump operator version to 0.0.12

This release includes:

• Bump base image (https://github.com/discourse/discourse_docker/commit/99e215415fa6a6af5aa1acc2cc396023cd951122)
• FIX: Worker connections are set on nginx.conf (https://github.com/discourse/discourse_docker/commit/edef7d317cff83a0e67ec10ea9f40d92fe258b67)
• PERF: Bump message_bus to 4.2 (https://github.com/discourse/discourse/commit/98a7fa3d1af8742f4f469f56de473e6c5a8fe218)
• Fix of post-deployment command, right before spawning unicorn workers, minimizing impact when accessing to the old schema.