fix(package): update @octokit/endpoint to version 5.1.0

Closes #47

Author: greenkeeper[bot]

package.json

@@ -36,7 +36,7 @@
   },
   "homepage": "https://github.com/octokit/request.js#readme",
   "dependencies": {
-    "@octokit/endpoint": "^4.0.0",
+    "@octokit/endpoint": "^5.1.0",
     "deprecation": "^1.0.1",
     "is-plain-object": "^3.0.0",
     "node-fetch": "^2.3.0",