Fixed author_email (PyPI was erroing with multiple emails)

Author: syrusakbary

setup.py

@@ -54,7 +54,7 @@ def run_tests(self):
     url='https://github.com/graphql-python/graphql-core',
     download_url='https://github.com/graphql-python/graphql-core/releases',
     author='Syrus Akbary, Jake Heinz, Taeho Kim',
-    author_email='Syrus Akbary <[email protected]>, Jake Heinz <[email protected]>, Taeho Kim <[email protected]>',
+    author_email='[email protected]',
     license='MIT',
     classifiers=[
         'Development Status :: 5 - Production/Stable',