chore: update helm version

[xazhao]

Note: This helm version is not guaranteed to work with the kubectl version in this branch.

However this layer version is outdated and not supposed to be used anymore. Helm version needs to be updated because it's impacted by the CVE https://security.snyk.io/vuln/SNYK-CHAINGUARDLATEST-HELM-7219926

It's bundled as dependency of CDK. If it's not fixed here, we need to ship a breaking change in main cdk repo which has more impact.

[shikha372]

we're using this layer in aws-cdk-lib if I'm not wrong, any change in here can lead to breaking change for the customers as well as it being used here in CDK.
https://github.com/aws/aws-cdk/blob/main/packages/aws-cdk-lib/lambda-layer-kubectl/lib/kubectl-layer.ts#L1. Though, EKS natively doesn't support this kubectl version, not sure if we still want to keep it to older version in main lib https://docs.aws.amazon.com/eks/latest/userguide/kubernetes-versions.html.

[xazhao]

Yes this layer is used in aws-cdk-lib and is outdated.
There are 3 ways to resolve it:

1. make kubectlLayer required from optional
2. update kubectlLayer default version
3. update helm version

All of them are breaking changes. 3) is the solution has least impact. Since this layer is not supported natively by EKS, the change impact is minimal.

[xazhao]

Similar with change as this PR #623

[mrgrain]

I'd argue (1) has the least impact. Yes, it will break builds. But at least it will break them transparently. Both (2) and (3) might or might not break a customer depending on the exact circumstances. However if it does, the failure will be much less transparent and a few steps removed. (1) has a guarantee to have zero impact on deployed resources. With (2) & (3) we have the potential to cause an outage to a customer.