Fix README

Author: ildus

README.md

@@ -4,8 +4,8 @@
 # testgres (async version)
 
 PostgreSQL testing utility. Only Python 3.5+ are supported. If you need older
-version of python or don't want to use async functions use original testgres
-from [https://github.com/postgrespro/testgres](https://github.com/postgrespro/testgres)
+version of python or don't want to use async functions use testgres from
+master branch.
 
 
 ## Usage