Add update date to the UI

[gsmet]

We need to add the update date to the UI so that we can easily see if a check is not run properly.

We could use pretty time and make the label red if things are too old (e.g. more than 3 days old for instance).

[gsmet]

Gonna be a bit more complicated than that as we don't really have a proper update date when the build is a success as we don't change anything in the issue. I think we should somehow update the issue even when we have a success. It could be by adding and removing a label for instance.

If we can get Quarkus GitHub App to handle GitHub Actions, it could be a nice experiment to change the current JBang script into a proper GH Action. The nice thing is that we could then centralize this code in one place and enhance it globally.