add troubleshooting

Author: f0ssel

github-upload-public-key/README.md

@@ -33,4 +33,4 @@ CODER_EXTERNAL_AUTH_0_CLIENT_SECRET=xxxxxxx
 CODER_EXTERNAL_AUTH_0_SCOPES="repo,workflow,admin:public_key"
 ```
 
-Note that the default scopes if not provided are `repo,workflow`.
+Note that the default scopes if not provided are `repo,workflow`. If the module is failing to complete after updating the external auth configuration, instruct users of the module to "Unlink" and "Link" their Github account in the External Auth user settings page to get the new scopes.