Auto-scroll logs while following the task's output in real time

[Jackenmen]

I think this is pretty common in the output of other CIs (GitHub Actions and AppVeyor do it, it's been a while since I used Travis CI, Circle CI, or Azure Pipelines but I believe they all do it as well). When you are at the bottom of the current task step, they continue to keep you at the bottom of those logs so that you can follow them in real-time easily. Due to this missing UX feature, it's been incredibly inconvenient for me to follow task output in real-time on Cirrus CI.

One thing to note about the implementation is that the auto-scroll should only happen if you're actually at the bottom of the logs, I wouldn't want my page to keep going down when I want to stop and look at some part of the logs while it's running.