Bump garden-ci-ubuntu to 0.11.9
Bump garden-ci-ubuntu to 0.11.9

[#156648201]

Signed-off-by: Danail Branekov <43f82d874965b9fe2876a1a864fffde1e64d6143@gmail.com>

cloudfoundry-incubator/garden-shed,cloudfoundry-incubator/garden-shed