docs(contributing) clarify PR quality for the contributor T-shirt
docs(contributing) clarify PR quality for the contributor T-shirt

See Kong/kong@8ed77f7308d823b321ef713cea0868040f9257b9

Co-Authored-By: Thibault Charbonnier <thibaultcha@me.com>

From #1078

Mashape/getkong.org,Mashape/getkong.org,Mashape/getkong.org