Spike: automated release process

At the moment, our process for releasing and publishing new versions is based on manual invocation of lerna CLI on a local developer machine, which comes with few issues:

• it requires admin permissions on GitHub because it pushes directly to master
• we are publishing from "dirty" git checkout that may contain extra files when compared to what is committed to git
• the releases are not peer-reviewed, only the person making the release can preview the changes

I would like us to improve this process and make it more automated. I am envisioning the following setup:

• The person initiating the release:
  • creates a new feature branch
  • runs lerna version --no-git-tag-version --no-push to bump up versions, update changelogs and create the release commit.
  • pushes the feature branch to GitHub and opens a new pull request.
• When the PR is approved, the release commit is merged to master in the usual way. No admin permissions are required.
• A build pipeline (powered e.g. by Azure Pipelines or GitHub Actions) detects a release commit and
  • Creates appropriate git tags (unfortunately, this is not supported by Lerna as of 2018-01-29)
  • Runs lerna publish from-git to publish packages to the npm registry

@strongloop/loopback-maintainers thoughts?

Start by reviewing the manual Lerna release process and the proposed lerna version --no-git-tag-version --no-push flow. Define how a merged release commit is detected, git tags are created, and lerna publish from-git runs in the build pipeline; done means releases are peer-reviewed and publishing no longer requires local admin access.