chore(deps): bump eventsource and webpack-dev-server

Bumps [eventsource](https://github.com/EventSource/eventsource) to 2.0.2 and updates ancestor dependency [webpack-dev-server](https://github.com/webpack/webpack-dev-server). These dependencies need to be updated together.


Updates `eventsource` from 0.1.6 to 2.0.2
- [Release notes](https://github.com/EventSource/eventsource/releases)
- [Changelog](https://github.com/EventSource/eventsource/blob/master/HISTORY.md)
- [Commits](EventSource/eventsource@v0.1.6...v2.0.2)

Updates `webpack-dev-server` from 3.1.9 to 3.11.3
- [Release notes](https://github.com/webpack/webpack-dev-server/releases)
- [Changelog](https://github.com/webpack/webpack-dev-server/blob/v3.11.3/CHANGELOG.md)
- [Commits](webpack/webpack-dev-server@v3.1.9...v3.11.3)

---
updated-dependencies:
- dependency-name: eventsource
  dependency-type: indirect
- dependency-name: webpack-dev-server
  dependency-type: direct:development
...

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Author: dependabot[bot]