Support a finalize command for monorepos

[rhuanbarreto]

Feature request

In monorepos, Chromatic generates lots of status checks for each project. But I can't setup in github to wait for all status checks to be green to allow the PR to be merged.

Proposed solution

LostPixel came with a good solution: https://docs.lost-pixel.com/user-docs/recipes/lost-pixel-platform/monorepo

It's a FINALIZE command that triggers the cloud service and the cloud service generates one status check that gets updated whenever all the other ones are green. This status check can be added to the list of required status checks for merging.

Alternative solutions

Today there are some alternatives:

• Run Chromatic with exitOnceUploaded: false and wait until the command fails or passes. This has a big CI cost for us because we need to wait for Chromatic response.
• Manually waiting for all status checks to pass before giving an approval. Not practical in monorepos as every contributor must know this rule (this is actually what we do today)
• Using workflows like wait-for-checks which incur in CI cost for polling github