1.1.0

chore(skaffold): trim dependencies of buildx script

The `docker-client` package includes the docker cli, docker-compose, and
some other dependencies.  It's safe for us to assume that
`skaffold-buildx-build` will only be run in environments where `docker`
is already available.

The `docker-buildx` package is just the `docker-buildx` plugin, which is
not in github actions runners by default, so it's necessary.

v1.0.1

direnv: Skip all setup if $CI is nonempty

v1.0.0

Warn when nix isn't installed