Add commit message guidelines to CONTRIBUTING.md
Add commit message guidelines to CONTRIBUTING.md

mikkeloscar/sway,ascent12/sway,taiyu-len/sway,4e554c4c/sway,ascent12/sway,mikkeloscar/sway,taiyu-len/sway,ptMuta/sway,1ace/sway,SirCmpwn/sway,1ace/sway,taiyu-len/sway,johalun/sway,1ace/sway,sleep-walker/sway,4e554c4c/sway,sleep-walker/sway,ascent12/sway