v1.3.2 (test)

Modify build-artifacts.yml to package libprism source

Instead of uploading the built `libprism.so` and `libprism.dylib`,
which still requires headers files to be built, Prism can upload the
full source, headers, and the Makefile as a tarball that can be used to
build libprism from source.

The reason default release artifacts are not enough is because some
source and header files are generated through Prism's rake tasks.