camelcase-keys & snakecases-keys inconsistent default behaviour

[boedy]

@sindresorhus @bendrucker

Both of your packages communicate a similar api, but you don't use the same defaults. The deep option for camelcase-keys is false where it is true for snakecase-keys. I would suggest standardising the default to prevent unsuspected behaviour as I experienced first hand.

I believe defaulting the deep option to true aligns with most preferences.