Add example query string from dev docs

Author: youmikoh

docs/oauth-workflow-example.md

@@ -42,7 +42,7 @@ async def install(shop_name: str):
     )
 ```
 
-4. To capture the `code`, set up a callback handler in your app. To exchange the temporary token for a permanent access token, supply the parameters from this request to the `request_token` function. 
+4. To capture the `code`, set up a callback handler in your app. To exchange the temporary token for a permanent access token, supply the parameters from this request to the `request_token` function. See an [example query string here](https://shopify.dev/apps/auth/oauth/getting-started#step-2-verify-the-installation-request) to be passed as the `request_params`.
 
 ```python
 @app.get("/auth/shopify/callback")