Update README.md

Signed-off-by: Olga Botvinnik <olga.botvinnik@gmail.com>

README.md

@@ -195,7 +195,7 @@ with:
 ```
 
 ### Minimal complete working github actions yaml file
-
+This minimal workflow clones the repo in question with the `actions/checkout@v1` step, and then runs `docker build -t myorg/myrepository .` with the `Dockerfile` present in the parent directory. In this case, it only builds it and does not push it (`push: false`). This can be useful for testing if the `Dockerfile` is valid in the first place and making sure there are no version conflicts.
 ```yaml
 name: Build Docker images
 on: [push, pull_request]