[pre-commit.ci] pre-commit autoupdate (#1605)

updates:
- [github.com/psf/black: 21.5b1 → 21.5b2](psf/black@21.5b1...21.5b2)

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

@@ -6,7 +6,7 @@ repos:
     hooks:
       - id: mixed-line-ending
   - repo: https://github.com/psf/black
-    rev: 21.5b1
+    rev: 21.5b2
     hooks:
       - id: black
   - repo: https://github.com/asottile/blacken-docs