[Request] Additonal installation method

[yozachar]

I've created an asdf plugin asdf-bin, which can help install multiple versions of bin, which developers might find very handy. So, in the installation section of the README.md, as an alternate/unofficial method you can add the possibility of installing bin using asdf.

## Installing

1. Download bin from the [releases](https://github.com/marcosnils/bin/releases)
2. Run ./bin install github.com/marcosnils/bin so bin is managed by bin itself
3. Run bin ls to make sure bin has been installed correctly. You can now remove the first file you downloaded.
4. Enjoy!

### Alternatively ...

If you're an [`asdf`](https://asdf-vm.com) user, you can simply follow these steps:

  ```console
  $ asdf plugin add bin
  $ asdf install bin latest
  $ asdf global bin latest
  $ bin --version
  bin version 0.16.2
  commit: d1213c11e63483174ed95308c9eb6372bb9b16e9
  built at: 2023-02-21T13:11:19Z
  built by: goreleaser
  .```

[marcosnils]

has it been a request for this? It shouldn't make a lot of sense for bin users to have multiple version of it.

I prefer no to merge this unless there's a clear need from more users. Thx for the kind request!

[dfang]

If you want to have multiple versions of bin, you can check rtx or asdf.

rtx plugin add bin https://github.com/joe733/asdf-bin.git
rtx ls-remote bin
rtx i bin@latest

I agree with marcosnils, It shouldn't make a lot of sense for multiple versions for tools like bin. a latest version should be enough. As they are not language runtimes like go, python. versions required for projects.