Reporting a bug on documented branch lyra2019

[manurampandit]

• I am reporting a bug

Expected Behavior
As mentioned in https://github.com/vega/lyra Readme, branch labelled lyra2019 should work.
Actual Behavior
The branch doesn't work as expected. For instance, not able to drag and drop the data source on the canvas.
Steps to reproduce behavior

1. Do a fresh checkout of repo
2. Switch to branch lyra2019
3. yarn install && yarn start
4. Open localhost:8080
5. Choose 'cars' as data source
6. Drag and drop any field on the canvas
7. You will encounter following issue: