This is a new flag introduced in `nix-eval-jobs`, which reduces runtime
for the `ping-maintainers` subcommand from 12 minutes to 3 minutes for
me.
The `--constituents` flag is not supported anymore with
`--no-instantiate`, but it doesn't seem to make a difference anyway.
Same for `--max-jobs` - I don't get a difference with or without it.
Removing the `foldl'` import because it is warned to be redundant after
switching to import the current nixpkgs instance, likely due to a newer
GHC version (?).
2e306afa68