Update the attrs pin annotation in tox.ini

Author: dmtucker

tox.ini

@@ -17,9 +17,9 @@ deps =
     pytest3.0: pytest ~= 3.0.0
     pytest3.1: pytest ~= 3.1.0
     pytest3.2: pytest ~= 3.2.0
-    pytest3.3: attrs < 19.2.0  # https://github.com/pytest-dev/pytest/issues/5900
+    pytest3.3: attrs < 19.2.0  # https://github.com/pytest-dev/pytest/issues/3223
     pytest3.3: pytest ~= 3.3.0
-    pytest3.4: attrs < 19.2.0  # https://github.com/pytest-dev/pytest/issues/5900
+    pytest3.4: attrs < 19.2.0  # https://github.com/pytest-dev/pytest/issues/3223
     pytest3.4: pytest ~= 3.4.0
     pytest3.5: pytest ~= 3.5.0
     pytest3.6: pytest ~= 3.6.0