Is it possible thanks to Github to automatically upload files to the site after a change?

Question

GitHub

The hosting has about 30 sites (for education). All work on CMS Joomla. All have the same template. Changes, additions and other improvements are constantly made to the template. If there are changes in the 1st template, then this change should appear on all the others.
Previously, for this task, everything was done primitively. Filzila - download... 1 time per month, generally ok. But lately there have been more changes. Accordingly, about version control, with this method, you can "keep silent" ...
There is only one way - to github. In general, everything is clear. But there is one question. Is it possible to automatically upload files with changes to the site using GitHub. That is, when changing a specific file (files), I first upload to my repository. And from there, each site clings to the file with the changes and uploads it to itself.
Question: how is it possible to implement this?
If I understand correctly, then: write a script that will monitor changes in the repository through crone, and then, if there are changes, upload the file?
Or is there a simpler implementation of this issue? Which is solved by a couple of lines of code...
Thank you all in advance for your help!

Answer 1

I think this is what you need:
https://circleci.com
https://travis-ci.org
True, they are conceived more like for testing, but they also know how to publish