package.json: Update webpack-dev-server

[DeeDeeG]

Summary of Changes

• update webpack-dev-server in package.json
• update yarn.lock
• yarn automatically alphabetized the package.json so I guess we can check in an alphabetized version once, and then we'll get small diffs from here on out, regardless of using yarn to update or just manually editing package.json

Checklist

• [ ] Tested Mobile Responsiveness
• [ ] Added Unit Tests
• [x] CI Passes
• [ ] Deploys to Heroku on test Correctly (Maintainers will handle)
• [ ] Added Documentation (Service and Code when required)

Screenshots

Before

After

[DeeDeeG]

Would like to merge this soonish. Not an important update, but just to have fewer PRs sitting around. Probably merging tomorrow or in a couple of days.

[DeeDeeG]

Merged now!