Support update-kubeconfig during cluster update

[coryflucas]

Fixes #3914

Allows update-kubeconfig to run while cluster is either ACTIVE or UPDATING. Only ACTIVE was supported currently. Presumably this is because the UPDATING status did not exist when the functionality was added. I confirmed that all information required to build the kubeconfig is present in the DescribeCluster output while in the UPDATING status.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-io]

Codecov Report

Merging #4036 into develop will not change coverage by %.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop    #4036   +/-   ##
========================================
  Coverage    93.96%   93.96%           
========================================
  Files          188      188           
  Lines        14525    14525           
========================================
  Hits         13649    13649           
  Misses         876      876           

Impacted Files	Coverage Δ
awscli/customizations/eks/update_kubeconfig.py	97.93% <100.00%> (ø)

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[coryflucas]

Anything I can do to assist in getting this approved?

[diranged]

How is it possible that this has languished since March? I can still reproduce this issue and it forces us to do some strange things to get around the issue. Can we get this merged?

[coryflucas]

Happy to rebase this if there is hope of getting merged

[mparent61]

Upvote from me to merge, just ran into this error trying to deploy during an EKS update. Anything I/we can do to assist getting this approved?

Thanks @coryflucas for fixing this!

[eladb]

This seems to also be impacting the AWS CDK's EKS module (see #6279)

[eladb]

@justnance can you look into this?

[coryflucas]

I went ahead and rebased the change in case someone is able to look at this

[kyleknap]

Thanks! Merging