Dynamic DigitalOcean versioning

[macobo]

Is your feature request related to a problem?

After digitalocean/marketplace-kubernetes#233 we're really close to being in do marketplace. However the version of the chart is hardcoded there. Let's automate upgrading

Describe the solution you'd like

Use the latest version of chart when deploying/upgrading in the scripts

Describe alternatives you've considered

Automate creating PRs against linked repo - but this will suck resources from the maintainers.

Additional context

cc @tiina303 you wanted to own this?

Thank you for your feature request – we love each and every one!

[tiina303]

Looks like there are some others who don't use the version either, e.g. fuziontech/marketplace-kubernetes@7c7d468
So this should be easy and fast.