chore(package): update npm-run-all to 4.1.5 to remove event-stream (#…

…5614)

event-stream had unknown code added to it, npm-run-all 4.1.5 was updated
to fix that. dominictarr/event-stream#116 for
more information

package.json

@@ -128,7 +128,7 @@
     "minimist": "^1.2.0",
     "node-sass": "^4.10.0",
     "npm-merge-driver-install": "^1.1.1",
-    "npm-run-all": "^4.1.2",
+    "npm-run-all": "^4.1.5",
     "postcss-cli": "^6.0.0",
     "proxyquireify": "^3.0.0",
     "qunit": "~2.5.1",