Update CI; no need to install rsync and openssh.

The shell executor is started in an healthy environment already;
the commands are needed mainly for the docker runner.
4 jobs for master in 2 minutes and 53 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #1007
build:lektor

00:02:47

 
  Staging
passed #1008
deploy
staging:testing

00:00:02

 
  Deploy
passed #1183
deploy manual
deploy:production

00:00:03

passed #1009
deploy manual
deploy:production

00:00:01