Update example of 'wp config create'

[man4toman]

In windows, when we use:
wp config create --dbname=wpclidemo --dbuser=root

It returns this error:

ERROR 2003 (HY000): Can't connect to MySQL server on 'localhost' (10061 "Unknown error")

This is due to the absence of a password, if we add dbpass to command, the error will be gone, like:

wp config create --dbname=wpclidemo --dbuser=root --prompt=dbpass

[schlessera]

Thanks for the PR, @man4toman !