Fix automatic package detection

See graphql-python#11 (comment)

Author: bendemaree

setup.py

@@ -45,7 +45,7 @@
     author="Syrus Akbary",
     author_email='[email protected]',
     url='https://github.com/graphql-python/graphql-ws',
-    packages=find_packages(include=['graphql_ws']),
+    packages=find_packages(exclude=["*.tests", "*.tests.*", "tests.*", "tests"]),
     include_package_data=True,
     install_requires=requirements,
     license="MIT license",