Update to wpcs 3.2

[srtfisher]

Description

I would like to see our package use WPCS 3.2 but there are some new sniffs that prevent that.

To address

• Update 4 letters for min prefix length WordPress/WordPress-Coding-Standards#2479 We use ai_ everywhere at Alley and this is now an invalid prefix.
• Remove wp-coding-standards/wpcs from the dependencies. Introduced in PHP Compatibility Should be Removed #57 to prevent dependent packages from upgrading.