Update CI EKS cluster to 1.18

Summary

Update our EKS cluster to 1.18

Upgrade docs - https://docs.aws.amazon.com/eks/latest/userguide/update-cluster.html

Currently our eks CI cluster is on version 1.17 which reached end-of-life with amazon on Nov 2 2021 https://docs.aws.amazon.com/eks/latest/userguide/kubernetes-versions.html#kubernetes-release-calendar

Details

Notice: 1.18 will EOL on February 18, 2022