Require setuptools, dingz/constants.py imports pkg_resources (#5)

Author: hroncok

setup.py

@@ -23,7 +23,7 @@
     author="Fabian Affolter",
     author_email="[email protected]",
     license="Apache License 2.0",
-    install_requires=["aiohttp<4", "async_timeout<4", "click"],
+    install_requires=["aiohttp<4", "async_timeout<4", "click", "setuptools"],
     packages=find_packages(),
     zip_safe=True,
     include_package_data=True,