docker: Build using Go 1.13
docker: Build using Go 1.13

syncthing/syncthing,imsodin/syncthing,AudriusButkevicius/syncthing,wweich/syncthing,syncthing/syncthing,AudriusButkevicius/syncthing,imsodin/syncthing,syncthing/syncthing,imsodin/syncthing,AudriusButkevicius/syncthing,imsodin/syncthing,wweich/syncthing,wweich/syncthing,AudriusButkevicius/syncthing,syncthing/syncthing,imsodin/syncthing,syncthing/syncthing,syncthing/syncthing,wweich/syncthing