Remove broken link to atrato.io
Remove broken link to atrato.io

This has been down since at least October 2018. See BEAM-5665

apache/beam,robertwb/incubator-beam,RyanSkraba/beam,chamikaramj/beam,chamikaramj/beam,lukecwik/incubator-beam,chamikaramj/beam,RyanSkraba/beam,lukecwik/incubator-beam,RyanSkraba/beam,apache/beam,lukecwik/incubator-beam,chamikaramj/beam,apache/beam,robertwb/incubator-beam,chamikaramj/beam,apache/beam,apache/beam,RyanSkraba/beam,robertwb/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,chamikaramj/beam,chamikaramj/beam,robertwb/incubator-beam,markflyhigh/incubator-beam,robertwb/incubator-beam,lukecwik/incubator-beam,lukecwik/incubator-beam,markflyhigh/incubator-beam,apache/beam,robertwb/incubator-beam,markflyhigh/incubator-beam,apache/beam,lukecwik/incubator-beam,RyanSkraba/beam,apache/beam,apache/beam,robertwb/incubator-beam,apache/beam,robertwb/incubator-beam,markflyhigh/incubator-beam,lukecwik/incubator-beam,iemejia/incubator-beam,markflyhigh/incubator-beam,robertwb/incubator-beam,robertwb/incubator-beam,markflyhigh/incubator-beam,chamikaramj/beam,RyanSkraba/beam,chamikaramj/beam,lukecwik/incubator-beam,iemejia/incubator-beam,RyanSkraba/beam,apache/beam,chamikaramj/beam,markflyhigh/incubator-beam