add PR guidelines
add PR guidelines

voxmedia/quill,Asana/quill-1,JoshBarr/quill,jayzawrotny/quill,DemocracyOS/quill,psiemens/quill,eXcomm/quill,DemocracyOS/quill,Benibur/quill,milqfm/quill,casetext/quill,dahal/quill,sferoze/quilljs,KentZheng/gitFlowTIB,studio666/quill,willrowe/quill,voxmedia/quill,KentZheng/testingflow,quilljs/quill,KentZheng/testingflow,smartsocialmedia/quill,voxmedia/quill,KentZheng/gitFlowTIA,Asana/quill-1,anovi/quill,tim-mc/quill,sferoze/quilljs,KentZheng/gitFlowTIB,kmoe/quill,casetext/quill,syungkeaw/quill,mobitroll/kahoot-quill,mobitroll/kahoot-quill,gutenye/quill,psiemens/quill,milqfm/quill,tim-mc/quill,sferoze/quilljs,quilljs/quill,praneybehl/quill,hampsterx/quill,willrowe/quill,fraywing/quill,jcppman/quill,sferoze/quilljs,kmoe/quill,quilljs/quill,willrowe/quill,fraywing/quill,KentZheng/gitFlowTIA,jziggas/quill,smartsocialmedia/quill