Update minimum supported kubernetes version to 1.12
1.11 is soon to be no longer supported by all our cloud targets.
- 1.13 is the current supported version from Kubernetes upstream, but that is expected to move to 1.14 this September with the release of 1.16 as latest stable.
- 1.11 is being dropped from GKE and the rollout to 1.12 has begun: https://cloud.google.com/kubernetes-engine/docs/release-notes#september_5_2019
- 1.11 is being dropped from EKS on November 4th: https://docs.aws.amazon.com/eks/latest/userguide/platform-versions.html
We should plan to update our documentation to reference 1.12 as the minimum supported version, and update all our tooling to use 1.13 versions of the kubernetes libraries. (The libraries and apis offer version compatibility back one version)