Plugin shadows --version option of helm install and helm template

Both `helm install` and `helm template` support a `--version` option used to specify the version of a chart to install:

--version string specify the exact chart version to install. If this is not specified, the latest version is installed

Unfortunately the current version of this package intercepts the `--version` argument and passes it to `kubeval`, which makes it impossible to give this argument to `helm template`:

https://github.com/instrumenta/helm-kubeval/blob/7476464518c34af0396fa9e330299f373202b7dc/scripts/run.sh#L10-L14

It would be great if there were a way to pass the `--version` argument to helm. I think the best way to achieve this would be by supporting the "end of options" flag, which is `--`. Using the `--` sends all arguments after it to helm without intercepting any of them.

I imagine the usage would look like:

helm kubeval myChart -- --version 1.0

This would pass the `--version 1.0` argument to helm, rather than printing the `kubeval` version.

The current version of `run.sh` nearly supports this. It has an `eoo` variable which it checks (complete with an appropriate `else` case), but it never actually checks for `--` or sets `eoo` to `1`.