add pyupgrade-docs to pre-commit-config

Author: boris

.pre-commit-config.yaml

@@ -9,6 +9,12 @@ repos:
     hooks:
     -   id: blacken-docs
         additional_dependencies: [black==20.8b1]
+-   repo: https://github.com/verhovsky/pyupgrade-docs
+    rev: v0.2.1
+    hooks:
+    -   id: pyupgrade-docs
+        args: [--py36-plus]
+        additional_dependencies: [pyupgrade==2.10.0]
 -   repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v3.4.0
     hooks: