Use stable core versions
Problem/Motivation
Following this thread on Slack we can investigate using stable core releases where possible, to mitigate against core problems affecting contrib pipelines.
An example was #3479160: 11.0.x yarn dependencies have mushroomed which would have caused all contrib testing to fail, had gitlab_templates been using the 11.x branch at that time.
When D10 was 'current':
https://git.drupalcode.org/project/gitlab_templates/-/jobs/2973468
With D11 as the 'current' version:
https://git.drupalcode.org/project/gitlab_templates/-/jobs/2985103