Indicate if any of the core components are out of date vs. the registry

[alexellis]

Indicate if any of the core components are out of date vs. the registry

Expected Behaviour

gateway image: ghcr.io/openfaasltd/gateway:0.2.13

Via the code we have in arkade for arkade chart upgrade, we could show whether the image was the latest.

Current Behaviour

End-users or our team have to work this out.

Possible Solution

Context

Having up to date components is important for bug fixes and for us being able to reproduce issues.