Update README

Author: peter-evans

README.md

@@ -38,9 +38,17 @@ action "Create Pull Request" {
   needs = "autopep8"
   uses = "peter-evans/create-pull-request@v1.0.0"
   secrets = ["GITHUB_TOKEN"]
+  env = {
+    PULL_REQUEST_BRANCH = "autopep8-patches"
+    COMMIT_MESSAGE = "autopep8 action fixes"
+    PULL_REQUEST_TITLE = "Fixes by autopep8 action"
+    PULL_REQUEST_BODY = "This is an auto-generated PR with fixes by autopep8."
+  }
 }
 ```
 
+The workflow in this repository created [this sample pull request](https://github.com/peter-evans/autopep8/pull/1).
+
 ## License
 
 MIT License - see the [LICENSE](LICENSE) file for details