Bump eventsource from 1.1.0 to 1.1.1 in /tools/test-lib/react-app (#881)

Bumps [eventsource](https://github.com/EventSource/eventsource) from 1.1.0 to 1.1.1.
- [Release notes](https://github.com/EventSource/eventsource/releases)
- [Changelog](https://github.com/EventSource/eventsource/blob/master/HISTORY.md)
- [Commits](EventSource/eventsource@v1.1.0...v1.1.1)

---
updated-dependencies:
- dependency-name: eventsource
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Tynan DeBold <[email protected]>