Can't execute shell script in AUR PKGBUILD

In the PKGBUILD file for an AUR I am working on, I get the following error in my package() function:

./install.sh: No such file or directory

here is the function:

package() {
	cd /opt/"$pkgname"/pymoab
	./install.sh
	python setup.py install
}

The file is in the directory, and it is called 'install.sh.cmake'. I have tried changing the command in the package() function multiple ways, including:

bash install.sh
bash install.sh.cmake
bash ./install.sh
bash ./install.sh.cmake
./install.sh
./install.sh.cmake
. ./install.sh
. ./install.sh.cmake

All give the same error. I originally wrote this as a set of shells scripts, which work well. In the shell script the command is:

bash install.sh

So I'm not sure why it doesn't work in the package() function. I am testing this on a fresh arch distro (junest: https://github.com/fsquillace/junest) All input appreciated. Let me know if I can provide more detail.