How autoscaling GitLab CI works on AWS Fargate

What this post added

Introduced a custom executor driver for GitLab Runner to enable autoscaling of CI jobs on AWS Fargate. This driver utilizes the AWS Fargate `run-task` action to schedule new tasks, where each task runs a container built from a specific image containing necessary build tools. The driver divides the CI job into Config, Prepare, Run, and Cleanup stages and includes capabilities for SSH connectivity between the driver and the build container. A limitation noted is the inability to run containers in privileged mode, preventing Docker-in-Docker on Fargate.