Change ignored cache dir for pytest 3.4.0

Committed via https://github.com/asottile/all-repos

.gitignore

diff --git a/.gitignore b/.gitignore
index 6fdf044..fc72fdb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,7 +2,7 @@
 *.iml
 *.py[co]
 .*.sw[a-z]
-.cache
+.pytest_cache
 .coverage
 .idea
 .project