Support monorepos with independent versions

[rickycodes]

This changes functionality to support MetaMask monorepos with an independent versioning strategy.

closes: #45

[mcmire]

LGTM. Thanks for hanging in there!

[mcmire]

I've been testing this out in three cases:

• Monorepo with fixed versions, using snaps-monorepo
• Monorepo with independent versions, using controllers (monorepo-poc branch). Note that we are no longer using action-create-release-pr to create release PRs but create-release-branch instead.
• Polyrepo package

I encountered a problem when attempting to release snaps-monorepo: https://github.com/mcmire/snaps-monorepo/actions/runs/3252758730/jobs/5339319338. But I made changes in 2cc1e0a...7e70bcd to fix this. Here is the successful release: https://github.com/mcmire/snaps-monorepo/actions/runs/3253016948/jobs/5339866555

I also encountered a problem with controllers: https://github.com/mcmire/controllers/actions/runs/3253182761/jobs/5340203034. I made changes here in 7e70bcd...021618a. I was able to get a successful build: https://github.com/mcmire/controllers/actions/runs/3253390324/jobs/5340619148. However, I realized that controllers was not using the latest version of npm-publish (which adds support for independent monorepos). Upon attempting to run create-release-branch again, however, I ran into this bug: MetaMask/create-release-branch#43. We need to fix this before we can continue testing this action.

I haven't gotten around to testing the polyrepo package case yet.

[rickycodes]

(by pinning to the last commit in this PR 021618a20fd0c0ee89269743d85dc72f92bbc110)

• I tested the polyrepo release flow in controllers here
• and similarity tested the fixed monorepo release flow in snaps-monorepo here

everything appears to have worked as expected. both runs skipped the get-release-packages step which is what we want (since these are not an independently versioned monorepo).

so backwards compatibly seems to be good!

[rickycodes]

I also tested this on a version of snaps-monorepo where I added release.config.json with an "independent" .versioningStrategy and that appears to have run correctly:

• It correctly ran the newly added get-release-packages.sh here
• It correctly determined the RELEASE_STRATEGY as independent here
• It correctly got a complete list of the packages to be published (in this case all since I did this with Create Release Pull Request) here
• It correctly created a single version tag and individual tags for each package here

[Gudahtt]

LGTM!