Fix Flow failure on CircleCI due to the number of workers

https://github.com/flowtype/flow-bin/issues/138#issuecomment-448416874 https://github.com/flowtype/flow-bin/issues/138#issuecomment-450367472 > This will stop flow from trying to consume too many virtual CPUs (which CircleCI doesn't actually provide), letting it run to completion without first running out of memory and killing its sub processes. The log output in CircleCI was: https://circleci.com/gh/bvaughn/react-devtools-experimental/201 ``` #!/bin/bash -eo pipefail yarn flow yarn run v1.10.1 $ /home/circleci/repo/node_modules/.bin/flow Launching Flow server for /home/circleci/repo Spawned flow server (pid=259) Logs will go to /tmp/flow/zShomezScirclecizSrepo.log Monitor logs will go to /tmp/flow/zShomezScirclecizSrepo.monitor_log Launching Flow server for /home/circleci/repo Spawned flow server (pid=361) Logs will go to /tmp/flow/zShomezScirclecizSrepo.log Monitor logs will go to /tmp/flow/zShomezScirclecizSrepo.monitor_log Launching Flow server for /home/circleci/repo Spawned flow server (pid=464) Logs will go to /tmp/flow/zShomezScirclecizSrepo.log Monitor logs will go to /tmp/flow/zShomezScirclecizSrepo.monitor_log Launching Flow server for /home/circleci/repo Spawned flow server (pid=567) Logs will go to /tmp/flow/zShomezScirclecizSrepo.log Monitor logs will go to /tmp/flow/zShomezScirclecizSrepo.monitor_log Lost connection to the flow server (0 retries remaining): -Out of retries, exiting! error Command failed with exit code 7. info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command. Exited with code 1 ```