bump garden-shed
bump garden-shed

[finishes #115957281]

Submodule src/github.com/cloudfoundry-incubator/garden-shed 3705db4..e42546e:
  > Increase Eventually timeout to mitigate flake

Signed-off-by: Petar Petrov <f705c0aa8aaf6bd313d55f7f3f71a8729abdecaa@gmail.com>

cloudfoundry-incubator/guardian-release,cloudfoundry-incubator/guardian-release,cloudfoundry-incubator/guardian-release