message: infra: fix typo in directory name
diff: @@ -43,7 +43,7 @@ act on, and run the following command:
  sudo systemctl start gha-self-hosted-update
  ```
  -If the contents of the `image/` directory were changed, an image rebuild will
  +If the contents of the `images/` directory were changed, an image rebuild will
  also be started. The new image will be used by each VM after they finish
  processing the current job.
  