Update package.json

[Braunson]

Updating the joi dependency

ref: #22

[zhouzi]

Thanks for the PR and sorry for the delay 🙏

That's too bad because ^17.4.0 matches 17.11.0 and would work out of the box if we:

1. Move joi to the peerDependencies so it relies on the project's version
2. Add joi to the devDependencies so it's installed when developing

In this case ^17.0.0 should work as this plugin uses very basic joi features that probably didn't receive a breaking change with a minor version update.