v3.13.0

Added

• Add no-string-refs rule (#341 @Intellicode)
• Add support for propTypes assigned via a variable in prop-types (#355)

Fixed

• Fix never option in prefer-es6-class
• Fix jsx-key false-positives (#320 @silvenon)

Changed

• Documentation improvements (#368 @lencioni, #370 @tmcw, #371)
• Update dependencies