Background:

Today, amphtml uses https://github.com/apps/forking-renovate to regularly update all devDependencies (and some dependencies) listed in the root package.json file and various sub-package level files. As of today, there have been close to ~1500 update PRs, all of which have been merged manually. Other than a very small number of breaking changes, all these PRs were rubber-stamp approved and merged after all CI checks were green.

Goal:

The purpose of this issue is to streamline the upgrade process, eliminate unnecessary manual toil, and require human intervention only while approving critical runtime dependencies or addressing breaking changes. This will build on the work done in #28322 to reduce the overall number of upgrade PRs. Here's a proposal:

• Enable automatic merging for renovate PRs via the automerge config setting (see docs)
  • Do not enable automatic merging of upgrades to AMP's dependencies (shipped with the runtime)
• Since AMP's PRs need one approving review, use the renovate-approve app to auto-approve PRs that pass CI checks
• Set renovate-approve as an owner of package.json and package-lock.json files

With this, upgrade PRs for devDependencies that pass all CI checks will be automatically approved and merged.