Bump karma-firefox-launcher from 1.3.0 to 2.0.0

Bumps [karma-firefox-launcher](https://github.com/karma-runner/karma-firefox-launcher) from 1.3.0 to 2.0.0.
- [Release notes](https://github.com/karma-runner/karma-firefox-launcher/releases)
- [Changelog](https://github.com/karma-runner/karma-firefox-launcher/blob/master/CHANGELOG.md)
- [Commits](https://github.com/karma-runner/karma-firefox-launcher/compare/v1.3.0...v2.0.0)

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

package.json

@@ -79,7 +79,7 @@
     "karma": "^5.0.1",
     "karma-chrome-launcher": "3.1.0",
     "karma-coverage-istanbul-reporter": "^3.0.0",
-    "karma-firefox-launcher": "^1.1.0",
+    "karma-firefox-launcher": "^2.0.0",
     "karma-mocha": "2.0.1",
     "karma-sourcemap-loader": "^0.3.7",
     "karma-webpack": "^4.0.0-rc.2",