Update .gitlab-ci.yml file

2 jobs for main-with-ci in 8 seconds (queued for 2 seconds)
Name Stage Failure
test Test
Created fresh repository.
Checking out 573874ec as main-with-ci...

Skipping Git submodules setup
Executing "step_script" stage of the job script
Using docker image sha256:3bc18509b0d661bf741d9a5eab895ff04b187c52b847d67985424a1575723eaf for docker-registry.wikimedia.org/buster:latest with digest docker-registry.wikimedia.org/buster@sha256:72eb2fd0244e8669b7cbbd77357aef5b3e515fb0f18282afd12dc5edea9ab114 ...
$ yarn install --ignore-engines
/usr/bin/bash: line 112: yarn: command not found
Cleaning up file based variables
ERROR: Job failed: exit code 1