Feature Request: Add `-h` short opt to `--help`

I'm just getting started trying out `chalice`, and I find I quite often `chalice -h` ... `chalice --help`.
This is a pretty trivial and non-harmful change, so unless there's a deep reason not to, I'd appreciate a `-h` short opt.

It's pretty easy with `click.help_option('-h', '--help')`

Start at the chalice CLI entry point and review how Click currently registers the --help option. Confirm that `chalice -h` is accepted and produces the same help output as `chalice --help`, then run the relevant CLI checks available in the project.

Written by the indexing model from the issue text.