Allow pre-release (EKS) kubernetes versions

[alanraison]

As described in helm/helm#9371, adding -0 to the SemVer string allows pre-release versions to be included in the permitted versions. This is necessary for installing the chart on EKS.

Closes #69

[ordovicia]

Hmm, my understanding is:

• v1.30.1-eks-1de2ab1 is a pre-release version. EKS should use v1.30.1+eks.1de2ab1 instead to stick to SemVer spec. Amazon and other cloud providers does not follow SemVer habitually.
• Helm and other tools, by default, ignores pre-release versions when determining if a version is in a range. It is correct behavior in the light of SemVer semantics.
• By adding -0 to SemVer range, we can make Helm count in pre-release versions.

[ordovicia]

Could you please add some comments and a link to helm/helm#9371 to describe the situation and why we need this workaround?

[alanraison]

Sorry, where do you mean for me to add comments? In the Chart or in the PR?

[ordovicia]

I mean adding comments to the Chart.
Chart users would be able to understand why kubeVersion includes -0 without navigating the Git history to this PR.

[alanraison]

Hmm, my understanding is:

• v1.30.1-eks-1de2ab1 is a pre-release version. EKS should use v1.30.1+eks.1de2ab1 instead to stick to SemVer spec. Amazon and other cloud providers does not follow SemVer habitually.
• Helm and other tools, by default, ignores pre-release versions when determining if a version is in a range. It is correct behavior in the light of SemVer semantics.
• By adding -0 to SemVer range, we can make Helm count in pre-release versions.

Yes this is correct. By using the tool vert, you can test the differences;

> vert ^1.20.0 v1.30.2-eks-db838b0
> echo $?
1
> vert ^1.20.0-0 v1.30.2-eks-db838b0
1.30.2-eks-db838b0
> echo $?
0

[superbrothers]

It may be possible to remove the kubeVersion itself. If we install Chart and it works fine, we can use it.