Merge pull request #114 from pre-commit/pre-commit-ci-update-config

[pre-commit.ci] pre-commit autoupdate

Author: asottile

.pre-commit-config.yaml

@@ -33,7 +33,7 @@ repos:
     -   id: add-trailing-comma
         args: [--py36-plus]
 -   repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v0.910-1
+    rev: v0.920
     hooks:
     -   id: mypy
         additional_dependencies: [types-all]