Change createComment to use octokit.rest API

Author: wolfy1339

app.js

@@ -5,7 +5,7 @@ export default (app) => {
   app.log.info("Yay! The app was loaded!");
 
   app.on("issues.opened", async (context) => {
-    return context.octokit.issues.createComment(
+    return context.octokit.rest.issues.createComment(
       context.issue({ body: "Hello, World!" })
     );
   });