Fix #47 by having metadata on the supported Python versions

Author: seratch

setup.py

@@ -26,7 +26,7 @@ def find_version(*file_paths):
       version=find_version('slackeventsapi', 'version.py'),
       description='Python Slack Events API adapter',
       url='http://github.com/slackapi/python-slack-events-api',
-      author='Slack Technologies',
+      author='Slack Technologies, Inc.',
       author_email='[email protected]',
       license='MIT',
       packages=['slackeventsapi'],
@@ -36,4 +36,18 @@ def find_version(*file_paths):
         'requests',
         'six',
       ],
+      classifiers=[
+          "Development Status :: 5 - Production/Stable",
+          "Intended Audience :: Developers",
+          "Topic :: Communications :: Chat",
+          "Topic :: System :: Networking",
+          "Topic :: Office/Business",
+          "License :: OSI Approved :: MIT License",
+          "Programming Language :: Python",
+          "Programming Language :: Python :: 2.7",
+          "Programming Language :: Python :: 3.5",
+          "Programming Language :: Python :: 3.6",
+          "Programming Language :: Python :: 3.7",
+          "Programming Language :: Python :: 3.8",
+      ],
       zip_safe=False)