How to: Verify images within a helm chart
The `arkade chart verify` command validates that all images specified are accessible on a remote registry and takes a values.yaml file as its input.

Successful checking of a chart with `image: ghcr.io/openfaas/cron-connector:TAG`:

```bash
arkade chart verify  -f ~/go/src/github.com/openfaas/faas-netes/chart/cron-connector/values.yaml

echo $?
0
```

There is an exit code of zero and no output when the check passes.

You can pass `--verbose` to see a detailed view of what's happening.

Checking of nested components, where two of the images do not exist `autoscaler.image` and `dashboard.image`:

```bash
arkade chart verify  -f ~/go/src/github.com/openfaas/faas-netes/chart/openfaas/values.yamlecho $?
2 images are missing in /Users/alex/go/src/github.com/openfaas/faas-netes/chart/openfaas/values.yaml

COMPONENT           IMAGE
dashboard           ghcr.io/openfaasltd/openfaas-dashboard:0.9.8
autoscaler          ghcr.io/openfaasltd/autoscaler:0.2.5

Error: verifying failed

echo $?
1
```

Supported:

* `image:` - at the top level
* `component.image:` i.e. one level of nesting

Not supported yet:
* Custom strings that don't match the word "image": `clientImage: `
* Split fields for the image and tag name i.e. `image.name` and `image.tag`
* Third-level nesting `openfaas.gateway.image`