downgraded zone.js, breaks ci

package.json

@@ -108,7 +108,7 @@
     "rxjs": "5.4.2",
     "ts-md5": "1.2.0",
     "webfontloader": "1.6.28",
-    "zone.js": "0.8.13"
+    "zone.js": "0.8.12"
   },
   "devDependencies": {
     "@angular/compiler": "4.2.6",

yarn.lock

@@ -7730,6 +7730,6 @@ zip-stream@^1.1.0:
     lodash "^4.8.0"
     readable-stream "^2.0.0"
 
-zone.js@0.8.13:
-  version "0.8.13"
-  resolved "https://registry.yarnpkg.com/zone.js/-/zone.js-0.8.13.tgz#f0822525fad941582a03bbfe71eb21740315ddd0"
+zone.js@0.8.12:
+  version "0.8.12"
+  resolved "https://registry.yarnpkg.com/zone.js/-/zone.js-0.8.12.tgz#86ff5053c98aec291a0bf4bbac501d694a05cfbb"