Update vulture from 0.27 to 0.28

pyup-bot · tony · commit 81e5831624ef · 2018-07-07T08:56:30.000-05:00
diff --git a/requirements/dev.txt b/requirements/dev.txt
@@ -1,3 +1,3 @@
 isort==4.3.4
 flake8==3.5.0
-vulture==0.27
+vulture==0.28
