Better error handling when the configuration file data structure is incorrect

[jakebolam]

Is your feature request related to a problem? Please describe.
When the configuration file datastructure is incorrect,the bot fails in weird and wonderful ways. e.g.

{
    "projectName": "coding_challenge-13",
    "projectOwner": "zeroDevs",
    "repoType": "github",
    "repoHost": "https://github.com",
    "files": [
        "README.md"
    ],
    "imageSize": 100,
    "commit": true,
    "contributors": [
        {
            "login": "The24thDS",
            "name": "David Sima",
            "avatar_url": "https://avatars0.githubusercontent.com/u/26633429?v=4",
            "profile": "https://github.com/The24thDS",
            "contributions": [
                "code",
                "bug",
                "review"
            ]
        },
        {
            "login": "mikeattara",
            "name": "Mike Perry Y Attara",
            "avatar_url": "https://avatars1.githubusercontent.com/u/31483629?v=4",
            "profile": "https://mikeattara.com",
            "contributions": [
                "ideas",
                "code",
                "review",
                "test"
            ]
        },
        {
            "login": "AkinAguda",
            "name": "Akinwunmi Aguda",
            "avatar_url": "https://avatars0.githubusercontent.com/u/39712415?v=4",
            "profile": "https://github.com/AkinAguda",
            "contributions": [
                "bug"
            ]
        },
        {
            "login": "jakebolam",
            "name": "Jake Bolam",
            "avatar_url": "https://avatars2.githubusercontent.com/u/3534236?v=4",
            "profile": "https://jakebolam.com",
            "contributions": [
                "question"
            ]
        },
        {
            "login": "aneagoie",
            "name": "Andrei Neagoie",
            "avatar_url": "https://avatars3.githubusercontent.com/u/10776230?v=4",
            "profile": "https://github.com/aneagoie",
            "contributions": [
                "bug",
                "code",
                "ideas",
                "review"
            ]
        },
        {
            "login": "MattCSmith",
            "name": "Matt Smith",
            "avatar_url": "https://avatars3.githubusercontent.com/u/6190356?v=4",
            "profile": "https://github.com/MattCSmith",
            "contributions": [
                "question",
                "bug",
                "code",
                "ideas",
                "review"
            ]
        },
        {
            "contributions": [
                "ideas"
            ]
        },
      ]
}

Technically valid JSON but the schema is busted.

Describe the solution you'd like
Provide great error messages, so users no whats wrong with the schema.

Even better: Auto fix it!

Additional context
See: https://sentry.io/all-contributors/github-bot/issues/859146506/?query=is%3Aunresolved

Also issues: zeroDevs/FullstackTrends_Challenge-13#182

[Berkmann18]

An approach to this would be:

try {
  JSON.parse(config);
} catch (err) {
  // auto-fix and/or log errors if it can't fix it
}

There are some interesting solutions in this SO post (although most are for only fixing quote issues).

https://jsontuneup.com/ might be a helpful example.

In any case, this comes down to the CLI dependency not being able to parse a malformed configuration file. I started looking into that and found a decent library that provides much more informative errors and which I'm currently exploiting to see if I can get an auto-fixer into the mix.

[jakebolam]

This also broke the schema. Specifying invalid contribution types in the JSON. See sentry: https://sentry.io/organizations/all-contributors/issues/957977140/events/50916998062/