Init github actions with helm

[marwan-at-work]

Testing github actions with helm charts

We don't completely understand how this ct tool is working. Docs for that are here: https://github.com/helm/chart-testing/blob/master/doc/ct_lint.md

[chriscoffee]

I've had to do the following:

• Rather than using with: fetch-depth: 0 it requires git fetch --prune --unshallow instead
• Because I bumped the version of kind/helm/helm-actions etc I then had to alter the apiVersion for the Deployment resources. I also had to add apiVersion to Chart.yaml as this is enforced now.
• I had to add tag back in and remove registry. Also removed this from deployment.yaml
• {{ default .Chart.appVersion }} on ln 56 should be {{ default .Chart.AppVersion }} so I sorted this.

[twexler]

Things to do after this merges:

1. Remove CircleCI integration
2. Remove requirements on CircleCI