gh: update to 2.2.0.

The new gh codespace commands allow creating, listing, connecting to, and otherwise managing your codespaces.

# list your codespaces
$ gh codespace list

# create a new codespace
$ gh codespace create --repo cli/cli

# start an interactive shell within a codespace
$ gh codespace ssh

What's new:
- Add repo delete command
- Add run cancel command
- Add gpg-key management commands
- Support logging in to github.localhost

(bsiegert)