[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/psf/black: 20.8b1 → 21.4b0](psf/black@20.8b1...21.4b0)
- [github.com/asottile/pyupgrade: v2.12.0 → v2.13.0](asottile/pyupgrade@v2.12.0...v2.13.0)

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -2,7 +2,7 @@
 # See https://pre-commit.com/hooks.html for more hooks
 repos:
 -   repo: https://github.com/psf/black
-    rev: 20.8b1
+    rev: 21.4b0
     hooks:
     - id: black
 -   repo: https://github.com/pre-commit/pre-commit-hooks
@@ -13,7 +13,7 @@ repos:
     -   id: check-yaml
     -   id: check-added-large-files
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v2.12.0
+    rev: v2.13.0
     hooks:
     -   id: pyupgrade
         args: [--py36-plus]