Add W504 to ignored autopep8 rules

Committed via https://github.com/asottile/all-repos
diff --git a/tox.ini b/tox.ini
index a4be8bf..c131e6f 100644
--- a/tox.ini
+++ b/tox.ini
@@ -21,4 +21,4 @@
 max-line-length=131
 
 [pep8]
-ignore=E265,E501
+ignore=E265,E501,W504