update download_url

Author: pegler

setup.py

@@ -18,6 +18,7 @@
     description='Python library to look up timezone from lat / long offline',
     long_description=README,
     url='https://github.com/pegler/pytzwhere',
+    download_url='https://github.com/pegler/pytzwhere/tarball/1.0',
     author='Matt Pegler',
     classifiers=[
         'Intended Audience :: Developers',