Pass arbitrary flags to `cargo-binstall`

[musjj]

When a tool is not available in https://crates.io, cargo-binstall requires you to specify where the git repository should be sourced from with --git:

• --git <URL> — Override how to fetch Cargo.toml package manifest.

  This skip searching crates.io and instead clone the repository specified and runs as if --manifest-path $cloned_repo is passed to binstall.

But we currently can't use this option with taiki-e/install-action, because the action does not allow you to control the flags passed to cargo-binstall.

[taiki-e]

Hmm, if you want to always install Rust crates from source, I recommend using cache-cargo-install-action (which supports installation from git url and caching) instead of this action. (See also #66)