Tie packaged helm chart versions e.g. hpcc-7.12.30.tgz to image version

It would be worth documenting issues to do with helm chart versions and image version.
(it often seems to lead to confusion at the moment).

1) document how to use a specific hpcc helm chart version:
e.g.
helm install myhpcc https://github.com/hpcc-systems/helm-chart/blob/master/docs/hpcc-7.12.30.tgz

(richardkchapman is 'docs' a typical/standard location for packaged versions ?)

2) Consider tying the image.version of packaged version to the same docker image version.
i.e. in hpcc-7.12.30.tgz set image.version=7.12.30-1 as well.

3) Warn against associated problems of using "latest" and other non-specific versioned tag names. e.g. it is a moving target. An image tag called "latest" may already be in the local cache, but not correspond to the same "latest" in the remote repo.
To avoid confusion when using a specific helm chart version