It seems you want to ask others how to run a gradle build in GitHub Action.
Just read the manual: Executing Gradle builds on GitHub Actions . But I think that it is not an issue to be raised in this Katalon user forum.
If you want to run $ gradle test task in a Katalon Studio project on GitHub Actions to test your com.kms.katalon.**-dependent classes, you need a Katalon Runtime Engine license and somehow you need to enable KRE to run on GitHub Actions. I have never tried that. I do not even know if it is possible or not.
In some projects, I do unit-tests of com.kms.katalon.**-independent calsses on GitHub Actions as a part of Pull-Request processing. I can do it without KRE, of course. On the other hand, I would never want to do unit-tests of com.kms.katalon.**-dependent classes on GitHub Actions, simply because I do not need it. I always make good efforts to minimize the size of com.kms.katalon.**-dependent classes, so the manual testing on my local machine using the junit4ks library inside Katalon Studio is enough. I do not need any CI cycle for my com.kms.katalon.**-dependent classes.