fixed responses version in order to support 2.6

Mika Lackman · iler · commit 12c82dac9caa · 2018-02-01T16:12:52.000+02:00
diff --git a/requirements-dev.txt b/requirements-dev.txt
@@ -1,7 +1,7 @@
 pytest>=2.9.2
 py>=1.4.26
 mock>=1.0.1
-responses>=0.3.0
+responses==0.3.0
 
 # flake8
 flake8>=2.6.2
