setup.py: Check correct Cython version; fix linting errors

Author: 1st1

setup.py

@@ -6,6 +6,11 @@
 import sys
 
 
+from setuptools import setup, Extension
+from setuptools.command.build_ext import build_ext as build_ext
+from setuptools.command.sdist import sdist as sdist
+
+
 if sys.platform in ('win32', 'cygwin', 'cli'):
     raise RuntimeError('uvloop does not support Windows at the moment')
 
@@ -17,11 +22,6 @@
         raise RuntimeError('uvloop requires Python 3.5 or 3.6b3 or greater')
 
 
-from setuptools import setup, Extension
-from setuptools.command.build_ext import build_ext as build_ext
-from setuptools.command.sdist import sdist as sdist
-
-
 VERSION = '0.9.2.dev0'
 CFLAGS = ['-O2']
 LIBUV_DIR = os.path.join(os.path.dirname(__file__), 'vendor', 'libuv')
@@ -117,9 +117,9 @@ def finalize_options(self):
                 raise RuntimeError(
                     'please install Cython to compile uvloop from source')
 
-            if Cython.__version__ < '0.24':
+            if Cython.__version__ < '0.28':
                 raise RuntimeError(
-                    'uvloop requires Cython version 0.24 or greater')
+                    'uvloop requires Cython version 0.28 or greater')
 
             from Cython.Build import cythonize