Dear GitHub: no YAML anchors, please

@yossarian don't even need to read it - my dumb ass tried this shit a few years back with gitlab and it is HORRIBLE.

YAML has a composition problem and tbqh ime if you find yourself reaching for anchors you've passed the point where YAML is expressive enough

@arichtman @yossarian not gh actions, but the last time I tried to use anchors, I gave up and used a templating step to generate the final yaml.
@rogerlipscombe @yossarian agree. Normally I've stayed the heck away from dynamically defining pipelines since it becomes quite opaque what's going to run and why. I'm considering using a build system though for it lately cause it seems a reasonable fit what with a DAG of reproducible, cached outputs