I just shared this link along with the GitHub link. That is why these upvotes are there. Every developer does not have a echojs account. I guess they create one if they want to comment. Have a nice day.
No, it switches to the PHP version if it exists and installs if it is not. For example on ubuntu PHP 7.1 to 7.3 are already installed in the github action environment, so it just switches to those versions, For PHP 5.6 and 7.0, it installs them.