chore: update pre-commit hooks (#230)

<!--pre-commit.ci start-->
updates:
- [github.com/kynan/nbstripout: 0.8.0 →
0.8.1](kynan/nbstripout@0.8.0...0.8.1)
<!--pre-commit.ci end-->

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

.pre-commit-config.yaml

@@ -76,7 +76,7 @@ repos:
   #         )$
 
   - repo: https://github.com/kynan/nbstripout
-    rev: 0.8.0
+    rev: 0.8.1
     hooks:
       - id: nbstripout
         args: [--extra-keys=metadata.kernelspec metadata.language_info.version]