chore(package): update karma-browserstack-launcher to version 1.6.0

Closes #252

Author: greenkeeper[bot]

package.json

@@ -53,7 +53,7 @@
         "jasmine-core": "^3.4.0",
         "js-yaml": "^3.13.1",
         "karma": "^4.2.0",
-        "karma-browserstack-launcher": "~1.4.0",
+        "karma-browserstack-launcher": "~1.6.0",
         "karma-chrome-launcher": "^3.0.0",
         "karma-coverage": "^1.1.2",
         "karma-firefox-launcher": "^1.1.0",