chore(*): do not install WebDriver for Firefox to avoid error on CI

See angular/webdriver-manager#303 for details.

package.json

@@ -33,7 +33,8 @@
     "test": "karma start karma.conf.js",
     "test-single-run": "npm test -- --single-run",
     "preupdate-webdriver": "npm install",
-    "update-webdriver": "webdriver-manager update",
+    "//": "Do not install the Firefox driver to work around https://github.com/angular/webdriver-manager/issues/303.",
+    "update-webdriver": "webdriver-manager update --gecko false",
     "preprotractor": "npm run update-webdriver",
     "protractor": "protractor e2e-tests/protractor.conf.js",
     "update-index-async": "node --eval \"var fs=require('fs'),indexFile='app/index-async.html',loaderFile='app/lib/angular-loader/angular-loader.min.js',loaderText=fs.readFileSync(loaderFile,'utf-8').split(/sourceMappingURL=angular-loader.min.js.map/).join('sourceMappingURL=lib/angular-loader/angular-loader.min.js.map'),indexText=fs.readFileSync(indexFile,'utf-8').split(/\\/\\/@@NG_LOADER_START@@[\\s\\S]*\\/\\/@@NG_LOADER_END@@/).join('//@@NG_LOADER_START@@\\n'+loaderText+'    //@@NG_LOADER_END@@');fs.writeFileSync(indexFile,indexText);\""