Update karma requirement in /packages/generator/app/templates

Updates the requirements on [karma](https://github.com/karma-runner/karma) to permit the latest version.
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma@v4.2.0...v4.3.0)

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

Author: dependabot-preview[bot]

packages/generator/app/templates/package.json

@@ -56,7 +56,7 @@
     "enzyme": "^3.10.0",
     "enzyme-adapter-react-16": "^1.14.0",
     "eslint": "^6.2.2",
-    "karma": "^4.2.0",
+    "karma": "^4.3.0",
     "karma-chai-plugins": "^0.9.0",
     "karma-electron": "^6.3.0",
     "karma-mocha": "^1.3.0",