Specify local files to include

netlify.toml

@@ -1,2 +1,3 @@
 [functions]
+  included_files = ["appFn.ts", "getPlaylistIdFromUrl.ts"]
   external_node_modules = ["@probot/adapter-aws-lambda-serverless", "probot", "express", "keyv", "formidable"]

netlify/functions/index.ts

@@ -3,7 +3,7 @@ import {
   createProbot
 } from '@probot/adapter-aws-lambda-serverless';
 
-import { appFn } from '../../app';
+import { appFn } from '../../appFn';
 
 const privateKey = (process.env.PRIVATE_KEY as string).replace(/\\n/gm, '\n');