fix: helm version must be semver

[morremeyer]

As noted in https://helm.sh/docs/topics/charts/#the-chartyaml-file, a helm chart's version must be semver 2.0.0.

Since semver 2.0.0 strictly prescribes the "{major}.{minor}.{patch}" format, the shell string interpolation is used to remove the v prefix.

[bokysan]

Thank you for this commit. I am well aware that semver is without the v prefix. However, based on my experience, having only numbers in version causes more issues than it brings benefits.

Now, I'm not against this change, but would just like to check in with you -- have you had any specific issues as to why we would change this now? If we do make this change, it will cause a lot of compatibility issues, that's why I want to make sure we do it properly.

[morremeyer]

@bokysan

However, based on my experience, having only numbers in version causes more issues than it brings benefits.

I'd be very interested to learn about the cases where that happens! I've never experienced any, my experience is the other way around 😁

have you had any specific issues as to why we would change this now

I'm bringing up this change now because I only recently discovered the project to send outgoing mail from my Kubernetes clusters, that's why I'm opening the PR right now.

I use renovate to update dependencies, which assumes that helm charts use semantic versioning since that's what helm defines. For charts that do not use semver, it will error since the version is invalid.

This can be worked around by manually configuring another versioning scheme for the dependency, but in my experience it's always been easier to make the chart use semver.

However, I do not know the workflows other people use, I assume you're much more familiar with them @bokysan. If there's good reason to not alter it too much, this might be a reason for e.g. a major release of the chart or a completely different approach.

I'm not aware of any compatibility issues with helm charts that are caused by making the versioning semver, so my initial assumption was that this could be handled as a bug fix.

Looking forward to your thoughts and learning more!