[pugz]

I've been using Depot for a while and I'm a fan. It has made our (GitHub Actions) builds a lot faster because the cache is always warm. It also helps a lot when building amd64 images from my arm64 Macbook - that's excruciatingly slow if I just run `docker build`.

My only complaint is more about GHA - I wish there was an easier way to build multiple unrelated images at the same time in a single GHA job. Running `depot build &` to background things is a bit fiddly when it comes to interleaved console output, exit codes, etc.