[dev] Raise setuptools requirement to >=38.2.3

Needed for pip wheel + setuptools.wheel.Wheel.install_as_egg.

setup.py

@@ -47,7 +47,7 @@ setup(
     python_requires = '>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*',
     namespace_packages = ['zc'],
     install_requires = [
-        'setuptools>=8.0',
+        'setuptools>=38.2.3',
         'pip',
         'wheel',
     ],