Admin: update setup.py to get version

setup.py

@@ -1,6 +1,17 @@
 from setuptools import setup, find_packages
+import os
+
+
+def get_version(rel_path):
+    here = os.path.abspath(os.path.dirname(__file__))
+    with open(os.path.join(here, rel_path), 'r') as f:
+        for line in f.readlines():
+            if line.startswith('__version__'):
+                delim = '"' if '"' in line else "'"
+                return line.split(delim)[1]
+        else:
+            raise RuntimeError('Unable to find version string.')
 
-from flake8_use_fstring import __version__
 
 extra_test = [
     'coverage==4.*',
@@ -25,7 +36,7 @@
 
 setup(
     name='flake8-use-fstring',
-    version=__version__,
+    version=get_version('flake8_use_fstring/__init__.py'),
     description='Flake8 plugin for string formatting style.',
 
     url='https://github.com/MichaelKim0407/flake8-use-fstring',