upgrade linters (#842)

* upgrade linters

* fix

Author: gaborbernat

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
 -   repo: https://github.com/ambv/black
-    rev: 18.6b1
+    rev: 18.6b2
     hooks:
     -   id: black
         args: [--line-length=99, --safe]
@@ -9,7 +9,7 @@ repos:
     rev: v0.2.0
     hooks:
     -   id: blacken-docs
-        additional_dependencies: [black==18.6b1]
+        additional_dependencies: [black==18.6b2]
         language_version: python3.6
 -   repo: https://github.com/asottile/seed-isort-config
     rev: v1.0.1
@@ -30,6 +30,6 @@ repos:
         additional_dependencies: ["flake8-bugbear == 18.2.0"]
         language_version: python3.6
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v1.3.0
+    rev: v1.3.1
     hooks:
     -   id: pyupgrade