Upgrade to bpaf 0.9.1

[pacak]

• use color scheme by default
• display help if no command is specified

atty create is replaced with is-terminal since the last conversation, error messages should be a bit better now.

[pacak]

Last commit supposed to generate full documentation (and docs.rs is fine with that mix of html/markdown), but github seems to reject most of it, you can see somewhat broken doc here: https://github.com/pacak/cargo-supply-chain

I guess that's a bug, will change it to make something github is happy with and update to 0.9.2....

[Shnatsel]

Hopefully down in the future bpaf could use the standard library's is_terminal function instead of the crate to reduce the supply chain footprint - it's adding quite a lot of entries to Cargo.lock. It's too early for that now because the function has only shipped in 1.70, and this would be a rather aggressive MSRV bump.

[pacak]

Looks good other than that, except I'm not a fan of the verbose CLI reference in the README.

Done, just the update now.

[Shnatsel]

Thanks!