Add contributing header, encourage branching
Add contributing header, encourage branching

brodul/hubot,hubotio/hubot,joshsobota/hubot,Arthraim/merlin,alex-zhang/hubot,eshamow/gutterbot,geoffreyanderson/hubot,hcxiong/hubot,wyncode/hubot,makii42/hubot,mauricionr/hubot,bradparks/hubot__github_chat_bot,ooohiroyukiooo/hubot,lisb/hubot,edorsey/hubot,tiagochiavericosta/hubot,WaleedAshraf/hubot,github/hubot,mujiansu/hubot,rafaell-lycan/Hubot-X9,Mattlk13/Hubot,gregkare/hubot,hubotio/hubot,AlexandrPuryshev/hubot,sdimkov/hubot,shinvdu/hubot,skcript/skubot,lisb/hubot,doudoupower/hubot,mrb/hubot,nandub/hubot,limianwang/hubot,voltsdigital/hubot,sharabash/hubot,Drooids/hubot,jasonkarns/hubot,julianromera/hubot,rmdelo/appboy-hubot,lukw00/hubot,plated/hubot,kkirsche/hubot,aslihandincer/hubot,bgranberry/hubot,ajschex/hubot,cameronmcefee/hubot,decaffeinate-examples/hubot,davidkassa/hubot,rlugojr/hubot,ykusumi/test-hubot,wieden-kennedy/hubot,ddmng/brazil82-hubot,jschell/hubot,mchill/hubot,zvelo/hubot,daudich/hubot,krahman/hubot,dopeboy/hubot,poppingtonic/hubot,ouadie-lahdioui/hubot,scboucher/hubot,scboucher/hubot,RiddickSky/hubot,ykelvis/hubot,vkhang55/hubot,alucardzhou/hubot,jasonrhodes/botzero,awbauer/hubot,CobyR/hubot,howprice/hubot,fgbreel/hubot,jianchen2580/hubot,melexis/melexis-hubot,kristenmills/hubot,fstehle/hubot,PropertyUX/nubot,Hartmarken/hubot,leohmoraes/hubot,chadfurman/hubot,lisb/hubot,GrimDerp/hubot,mutewinter/hubot,craig5/hubot,decaffeinate-examples/hubot,mcanthony/hubot,minted/hubot,michaelansel/hubot,ClaudeBot/hubot,danielcompton/hubot,taojuntjpp/hubot,nandub/hubot,cycomachead/hubot,msound/hubot,pchaigno/hubot,ajayanandgit/hubot,Snorlock/hubot,eetuuuu/hubot,keyvanakbary/hubot,github/hubot,PropertyUX/nubot,iDTLabssl/hubot,hotrannam/hubot,blackwellops/hubot,RavenB/hubot,kgrz/hubot,mjurczyk/hubot,codydaig/hubot