Docs: Add examples of push configurations

[stuartleeks]

Add examples with explanations for different combinations of push/filters etc

[y3rsh]

This would be helpful. The default push behavior on GitHub actions makes me think I should go ahead and let my workflow that only lints (on pushes and PRs) push the container image? Or should I push: never on workflows like my lint workflow that are only a check?

If my branch has a change to the devcontainer, will that change cascade into some other branch because of the push? Loving this by the way! 😊 ❤️