Update @octokit/rest version, fixes #32

Author: Rachel Macfarlane

package.json

@@ -184,7 +184,7 @@
   },
   "dependencies": {
     "vscode": "^1.1.18",
-    "@octokit/rest": "^15.2.6",
+    "@octokit/rest": "^15.8.0",
     "dugite": "^1.63.0",
     "markdown-it": "^8.4.0",
     "git-credential-node": "^1.1.0",