message: docs: add package include clarification
diff: @@ -59,8 +59,14 @@ The plugin only needs to know where your `next.config.js` file is located. Note
  custom:
  serverless-nextjs:
  nextConfigDir: "/dir/to/my/nextApp"
  +
  +package:
  + include:
  + - sls-next-build/*
  ```
  +Make sure you include `sls-next-build/*` as this is where the compiled page handlers will be.
  +
  ### Next configuration
  In your `next.config.js` make sure the configuration is set like:
  