Add downstream stage to gitlab ci

4 jobs for auto_docker_images in 9 minutes and 33 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Install
passed #1380
install

00:04:54

 
  Test
passed #1382
linux:test:mysql

00:02:27

passed #1381
linux:test:psql

00:02:24

 
  Build
passed #1383
linux:amd64

00:02:09