Show workflow summary in UI

[dkfellows]

It would be really nice if the summary page for a workflow was visible in the VSCode UI. Yes, I see the link, but being able to pick up on warnings and errors issued by the workflow more obviously would be great as improving visibility for problems discovered by tooling is always useful (though not to the point of raising it to obnoxiousness).

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For example, I have a step in one of my workflows that effectively issues:

##[warning](mainwindow.cpp):TODO: check what this csv file was for

to the workflow log, which gets surfaced in the Github UI as:

What I'd like is to be able to see that sort of thing when I click on the workflow (and not one of its components) in the Github Actions panel in the sidebar. Effectively, it would be just loading a webpage that already exists, or at least part of it. (Mind you, I don't know if that information is conveniently surfaced in the Github API. If it isn't, that's an omission there too.)

[alexr00]

@dkfellows do you already have a GitHub Actions view in the sidebar? If so, that's coming from a different extension!