Updates Jest to 20.0.4.

[futuremint]

Also updates jest snapshots.

[interactivellama]

Getting this in heroku:

-----> Node.js app detected
-----> Creating runtime environment
       
       NPM_CONFIG_LOGLEVEL=error
       NPM_CONFIG_PRODUCTION=false
       NODE_VERBOSE=false
       NODE_ENV=production
       NODE_MODULES_CACHE=true
-----> Installing binaries
       engines.node (package.json):  >=4.4.0
       engines.npm (package.json):   ^3.9.0
       
       Resolving node version >=4.4.0 via semver.io...
       Downloading and installing node 8.1.2...
gzip: stdin: unexpected end of file
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now
-----> Build failed
       
       We're sorry this build is failing! You can troubleshoot common issues here:
       https://devcenter.heroku.com/articles/troubleshooting-node-deploys
       
       Some possible problems:
       
       - Dangerous semver range (>) in engines.node
       https://devcenter.heroku.com/articles/nodejs-support#specifying-a-node-js-version
       
       Love,
       Heroku
       
 !     Push rejected, failed to compile Node.js app.
 !     Push failed

https://dashboard.heroku.com/pipelines/22a311ed-7832-4b2d-8997-3e9242544b73
Previous PR seemed fine.

[futuremint]

Weird, I definitely didn't touch that part of package.json here. I'll investigate more if I have time tomorrow.

[interactivellama]

Maybe they just happened to update Travis to Node 8.x by default.

[futuremint]

Yes, if you look in the error log it was running Node 8.1.2... not sure we're ready for that so I'm keeping it at 6.x for now.