working_directory parameter isn't respected

[Adam Trager]

Using version 1.29.0

cypress/run doesn't appear to be respecting the working_directory parameter, the runner is unable to find the start command which it would be able to if it were in the correct directory.

- cypress/run:
          attach-workspace: true
          no-workspace: true
          yarn: true
          working_directory: app
          start: yarn start
          wait-on: 'http://localhost:3000'