chore: bump mitt from 2.1.0 to 3.0.1

Bumps [mitt](https://github.com/developit/mitt) from 2.1.0 to 3.0.1.
- [Release notes](https://github.com/developit/mitt/releases)
- [Commits](developit/mitt@2.1.0...3.0.1)

---
updated-dependencies:
- dependency-name: mitt
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

packages/_test/package.json

@@ -43,7 +43,7 @@
  "@contentful/f36-tokens": "^4.0.0",
  "emotion": "^10.0.17",
  "lodash": "^4.17.15",
- "mitt": "2.1.0"
+ "mitt": "3.0.1"
  },
  "peerDependencies": {
  "@contentful/app-sdk": "^4.2.0",