setup: fix MANIFEST usage

See [1].

1. https://stackoverflow.com/questions/3596979/manifest-in-ignored-on-python-setup-py-install-no-data-files-installed

Part of #238

Author: DifferentialOrange

setup.py

@@ -72,6 +72,7 @@ def find_version(*file_paths):
     name="tarantool",
     packages=["tarantool"],
     package_dir={"tarantool": os.path.join("tarantool")},
+    include_package_data=True,
     version=find_version('tarantool', '__init__.py'),
     platforms=["all"],
     author="tarantool-python AUTHORS",