It might be the instructions for install a bit off but I've tested on MacOS and Ubuntu (both BASH)... Which method is your install? If it's Docker Compose ( https://github.com/forbesmyester/esqlate#docker-compose-meth... ) it has a BASH line there in the README that does the checkout for you.
You may want to revisit how you do this. At the very least use git submodules so a particular version of your code pulls the correct version of a dependency.