[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/google/yamlfmt: 884e367e8fae92b238653fd950a54d235d418e4e → b5ca1890231d5e1e5181fef75a1be609d1e25029](google/yamlfmt@884e367...b5ca189)

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -17,7 +17,7 @@ repos:
       - id: check-yaml
       - id: check-added-large-files
   - repo: https://github.com/google/yamlfmt
-    rev: 884e367e8fae92b238653fd950a54d235d418e4e # frozen: v0.20.0
+    rev: b5ca1890231d5e1e5181fef75a1be609d1e25029  # frozen: v0.21.0
     hooks:
       - id: yamlfmt
   - repo: https://github.com/asottile/pyupgrade