feat: Initial webhook-event-check feature

[MaximDevoir]

A hook-check feature will warn developers if they are attempting to listen to an event their GitHub App is not subscribed to.

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100% unit tested when running yarn run jest --coverage check-event.test.ts.

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Example warning of an invalid event name (e.g. typo):

Example warning if an application is not connected to the Internet or bad configuration settings:

Limitations

• Event-check is only capable of checking the base part of an event - the text before the period, and not the action part of the event. For example, a Probot app may want to listen for new issues being opened using app.on('issues.opened, ...). Event-check will warn the user if the GitHub App is not subscribed to the issues event - but will not verify if the action (opened) is valid.

Closes #1042

[MaximDevoir]

Question: I've been thinking about this a bit, should the feature be renamed to webhook-event-check? I renamed it from webhook-check to event-check, but I'm wondering if that is the best name.

[gr2m]

Naming is hard :) I like webhook-event-check, it's the most explicit.

[gr2m]

Let us know when this PR is ready for review. If you are still working on it, can you prefix the pull request with [WIP] or 🚧?

[MaximDevoir]

OK, I think it's ready for your review.

[probotbot]

🎉 This PR is included in version 9.7.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[gr2m]

@MaximDevoir fyi, I'll have to remove the feature for now as it become a blocker for our serverless/function milestone. But I created a follow up issue to find another solution: #1435