bump tini to version 0.18.0 and haproxy to version 1.8.16 (#608)
bump tini to version 0.18.0 and haproxy to version 1.8.16 (#608)

* bump tini to version 0.18.0 and haproxy to version 1.8.15

* bump haproxy to version 1.8.16

* bump haproxy to version 1.8.18

* bump haproxy to version 1.8.19

vixns/marathon-lb,vixns/marathon-lb,mesosphere/marathon-lb,mesosphere/marathon-lb,vixns/marathon-lb,mesosphere/marathon-lb