chore: bump the development-dependencies group with 3 updates

Bumps the development-dependencies group with 3 updates: [check-engines](https://github.com/kruppel/check-engines), [karma](https://github.com/karma-runner/karma) and [karma-firefox-launcher](https://github.com/karma-runner/karma-firefox-launcher).


Updates `check-engines` from 1.5.0 to 1.6.0
- [Commits](kruppel/check-engines@v1.5.0...v1.6.0)

Updates `karma` from 6.4.2 to 6.4.4
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma@v6.4.2...v6.4.4)

Updates `karma-firefox-launcher` from 2.1.2 to 2.1.3
- [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@v2.1.2...v2.1.3)

---
updated-dependencies:
- dependency-name: check-engines
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: development-dependencies
- dependency-name: karma
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: development-dependencies
- dependency-name: karma-firefox-launcher
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: development-dependencies
...

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

package.json

@@ -8,12 +8,12 @@
     "babel-loader": "^6.4.0",
     "babel-preset-es2015": "^6.24.0",
     "chai": "^3.0.0",
-    "check-engines": "^1.5.0",
+    "check-engines": "^1.6.0",
     "dotcom-tool-kit": "^3.4.2",
-    "karma": "^6.4.2",
+    "karma": "^6.4.4",
     "karma-chai": "^0.1.0",
     "karma-cli": "^1.0.1",
-    "karma-firefox-launcher": "^2.1.2",
+    "karma-firefox-launcher": "^2.1.3",
     "karma-mocha": "^1.3.0",
     "karma-sinon": "^1.0.5",
     "karma-webpack": "^2.0.3",