* Start adopting Yarn workspaces
My plan is to move the existing package into a workspace and then split
out the things that really ought to be their own packages. For example,
the demo site and the experiments really ought to be separate.
Fix lint command
* Use workspaces in CI
* Fix deploy for monorepo
* Use GitHub Actions only
This retires Travis, and starts upload screenshot diffs when integration
tests fail.
* Use screenshots that match CI font rendering
* Run tests on Node 12
* Experiment with action to run IA tests
* Split out IA tests
* Don't try on push
* Also on push
* Make an error an error
* Introduce failing test
* Return an error exit code
* Remove failing test
