Include/exclude by topic or tag

[mikebell90]

It's nice to be able use say a github topic to include/exclude

[brendan-kellam]

Heya - yea I could see this fitting into the config as something like the following:

{
    "$schema": "./schemas/v2/index.json",
    "repos": [
        {
            "type": "github",
            // Include repositories that have at least one of the following topics.
            "topics": [
                "topic-1",
                "topic-2"
            ],
            "exclude": {
                // Exclude repositories that have at least one of the following topics.
                "topics": [
                    "topic-3"
                ]
            }
        }
    ]
}

// result: index repositories that have either topic-1 or topic-2 (or both) and do not have topic-3

GitLab has the same concept, so we could support it there as well.