chore(eks): update eks instance type list with max pods

[SanderKnape]

I'm unable to spin up EKS worker nodes with T3 instances. I noticed the MAX_PODS instance list is way behind.

The information in this list is directly copied from: https://github.com/awslabs/amazon-eks-ami/blob/master/files/eni-max-pods.txt

Pull Request Checklist

• Testing
  • Unit test added (prefer not to modify an existing test, otherwise, it's probably a breaking change)
  • CLI change?: coordinate update of integration tests with team
  • cdk-init template change?: coordinated update of integration tests with team
• Docs
  • jsdocs: All public APIs documented
  • README: README and/or documentation topic updated
  • Design: For significant features, design document added to design folder
• Title and Description
  • Change type: title prefixed with fix, feat and module name in parens, which will appear in changelog
  • Title: use lower-case and doesn't end with a period
  • Breaking?: last paragraph: "BREAKING CHANGE: <describe what changed + link for details>"
  • Issues: Indicate issues fixed via: "Fixes #xxx" or "Closes #xxx"
• Sensitive Modules (requires 2 PR approvers)
  • IAM Policy Document (in @aws-cdk/aws-iam)
  • EC2 Security Groups and ACLs (in @aws-cdk/aws-ec2)
  • Grant APIs (only if not based on official documentation with a reference)

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license.

[SanderKnape]

Just noticed the EKS module needs some more updates. Version 1.11 is listed as the latest version, and the AMI IDs for the EKS AMIs are out of date.

Also, Kubernetes 1.13 was released on EKS yesterday. The UI says that 1.12 is "default". The CDK defaults to a "LATEST_KUBERNETES_VERSION" variable: should that be changed to a "DEFAULT_KUBERNETES_VERSION" variable instead?

I would also suggest to remove the mention of version 1.10 (and maybe even 1.11) from the CDK. Thoughts?

I can append this PR with the changes.

[rix0rrr]

Thanks for this. The other changes in a different PR please.