[internal] setup automated releases

[williaster]

Releases are currently performed manually which requires the following

• Install all dependencies across all packages
• Build all packages
• Publish to npm
• Update the change log with all the changes
• Publish a new version of the docs by building the next app on a separate branch & pushing to github pages
• Possibly notifying users a release was available

This can go wrong in all sorts of ways:

• You accidentally didn’t have the latest branch
• You had a stale yarn.lock file which resulted in a bad build
• You forgot to run linting or testing, so you published an invalid version
• Everyone who publishes needs credentials for git (tags) and npm (packages), and 2-factor auth makes this more likely to fail which could result in a partial publish (some packages, not others)
• You could forget how to do a step if you hadn’t done it for a few weeks

As a result, we often stack up multiple features to warrant the trouble of a release. But this delays features for users who have to ask for releases (ex, ex).

Ideally we can automate all of this.

[hshoff]

completed in #1073