[pre-commit.ci] pre-commit autoupdate (#128)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -32,7 +32,7 @@ repos:
     -   id: rst-inline-touching-normal
     -   id: text-unicode-replacement-char
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v2.20.0
+    rev: v2.21.0
     hooks:
     -   id: pyupgrade
         args: [--py36-plus]