Linting tests should include linting the rendered yaml from the helm templates

[tvories]

@kabakaev had a good suggestion about linting the rendered yaml during the testing actions.

• The github actions should perform a lint test on the rendered helm templates.

[jessebot]

At the time this was opened, this was our current linting and tests:
https://github.com/nextcloud/helm/blob/fddf924cb4fa3f0422bc1ed1073761b3b45f66d3/.github/workflows/lint-test.yaml

Now our linting ad tests look like this:
https://github.com/nextcloud/helm/blob/34fc2dfad665712bf379c84150f4b93cdbcea0f4/.github/workflows/lint-test.yaml

The chart now gets installed a few different ways (except for with redis enabled, which we need to do as per #604). The installation should actually catch any remaining linting issues. Is it safe to close this?