Bump karma-firefox-launcher from 1.3.0 to 2.1.2

Bumps [karma-firefox-launcher](https://github.com/karma-runner/karma-firefox-launcher) from 1.3.0 to 2.1.2.
- [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](karma-runner/karma-firefox-launcher@v1.3.0...v2.1.2)

---
updated-dependencies:
- dependency-name: karma-firefox-launcher
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

package.json

@@ -28,7 +28,7 @@
     "jasmine-sinon": "~0.4.0",
     "karma": "^4.4.1",
     "karma-chrome-launcher": "^3.1.0",
-    "karma-firefox-launcher": "^1.3.0",
+    "karma-firefox-launcher": "^2.1.2",
     "karma-jasmine": "^2.0.1",
     "karma-jasmine-sinon": "^1.0.4",
     "minimist": "^1.2.5"