add `clip-copy-mime-type` attribute to README
add `clip-copy-mime-type` attribute to README
dtagdev1/ng-clip,ptheofan/ng-clip,Falci/ng-clip,asafdav/ng-clip,huayun321/ng-clip,asafdav/ng-clip,Falci/ng-clip,ptheofan/ng-clip,huayun321/ng-clip,dtagdev1/ng-clip