Install: Requires bun installation

[jeffgca]

If I run

hellhub --help

I get

➜ ~ hellhub --help
env: bun: No such file or directory

This is resolved by installing bun, so maybe the fix is just to explain in the readme that bun is required ( for now )

[fabio-nettis]

@jeffgca I surely do wonder why bun should be required, maybe the fact that we use Bun.argv but that should run on node just fine.

[fabio-nettis]

@jeffgca What package manager and command have you used to install the cli?

[jeffgca]

I just used npm, and previously had no bun installation. Installing bun fixed everything, so I think this is just an installation instructions gap?