only add labels to opened prs
only add labels to opened prs

Signed-off-by: Jessica Frazelle <136e3cf1ab6a4dc9cd25784ffe7ab05af45d9f77@docker.com>

SvenDowideit/leeroy,docker/leeroy,Graylog2/leeroy,SvenDowideit/leeroy,michaelneale/leeroy,michaelneale/leeroy,jfrazelle/leeroy,mjbrender/leeroy,EIrwin/leeroy,jfrazelle/leeroy,hawky-4s-/leeroy,EIrwin/leeroy,docker/leeroy,mjbrender/leeroy,hawky-4s-/leeroy