upgrade heroku-self-ping

Author: Amoki

Diff for: package.json

@@ -25,7 +25,7 @@
     "anyfetch-hydrater": "^2.2.0",
     "async": "0.9.x",
     "exec-sync": "^0.1.6",
-    "heroku-self-ping": "^1.1.1",
+    "heroku-self-ping": "^1.1.2",
     "restify": "~2.8.5",
     "supertest": "^0.15.0"
   },