fix(package): update probot to version 4.1.0

Closes #18

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
   },
   "dependencies": {
     "argv-split": "^2.0.1",
-    "probot": "^3.0.2",
+    "probot": "^4.1.0",
     "ramda": "^0.25.0",
     "request": "^2.83.0",
     "request-promise": "^4.2.2"