tox: use old attrs with pytest41

blueyed · blueyed · commit 9d701d563cf2 · 2019-10-16T22:12:08.000+02:00
diff --git a/tox.ini b/tox.ini
@@ -28,6 +28,7 @@ deps =
     coverage: coverage-enable-subprocess
 
     pytest41: pytest>=4.1,<4.2
+    pytest41: attrs==17.4.0
     xdist: pytest-xdist>=1.15
 
 setenv =
