Extend API to check the state after calling /v1/update

[JensWinkler91]

Is your feature request related to a problem? Please describe.

I update my docker container by sending a request from a react app to <domain>/v1/update.
This works fine.

However, I don't receive any response whether it finished with success or failed.
I also don't know the version of each container.

I can't provide any feedback (.e.g. if the update succeeded or not) to the user without any information about the current state.

Describe the solution you'd like

The request /v1/update can return the state of the update for each image:

E.G.

{
     "errors": [
           "image": "mongo",
           "tag": "6.0.0" 
     ],
    "success": [
               "image": "nginx",
               "tag_before": "2.0.0"
               "tag_after": "3.1.8" 
      ]
}

Describe alternatives you've considered

Change the request /v1/update from blocking to non blocking.
Add another route GET /v1/update/state to fetch the current state of the triggered update.

Additional context

Thanks for your work!

[github-actions]

Hi there! 👋🏼 As you're new to this repo, we'd like to suggest that you read our code of conduct as well as our contribution guidelines. Thanks a bunch for opening your first issue! 🙏