Rename CHANGES.txt -> CHANGES.rst

Author: asvetlov

CHANGES.txt renamed to CHANGES.rst

@@ -41,7 +41,7 @@ def read(f):
       version=version,
       description=("jinja2 template renderer for aiohttp.web "
                    "(http server for asyncio)"),
-      long_description='\n\n'.join((read('README.rst'), read('CHANGES.txt'))),
+      long_description='\n\n'.join((read('README.rst'), read('CHANGES.rst'))),
       classifiers=[
           'License :: OSI Approved :: Apache Software License',
           'Intended Audience :: Developers',