Merge pull request #15357 from twbs/update-saucelabs

bump grunt-saucelabs to ~8.4.0

package.json

@@ -54,7 +54,7 @@
     "grunt-html-validation": "~0.1.18",
     "grunt-jekyll": "~0.4.2",
     "grunt-jscs": "~1.0.0",
-    "grunt-saucelabs": "~8.3.3",
+    "grunt-saucelabs": "~8.4.0",
     "grunt-sed": "~0.1.1",
     "load-grunt-tasks": "~1.0.0",
     "npm-shrinkwrap": "^200.0.0",

test-infra/npm-shrinkwrap.json

@@ -3336,8 +3336,8 @@
       }
     },
     "grunt-saucelabs": {
-      "version": "8.3.3",
-      "resolved": "https://registry.npmjs.org/grunt-saucelabs/-/grunt-saucelabs-8.3.3.tgz",
+      "version": "8.4.0",
+      "resolved": "https://registry.npmjs.org/grunt-saucelabs/-/grunt-saucelabs-8.4.0.tgz",
       "dependencies": {
         "colors": {
           "version": "0.6.2",