[pre-commit.ci] pre-commit autoupdate (#20)

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -33,7 +33,7 @@ repos:
   hooks:
     - id: nbstripout
 - repo: https://github.com/nbQA-dev/nbQA
-  rev: 1.6.1
+  rev: 1.6.4
   hooks:
     - id: nbqa-black
     - id: nbqa-isort