fix string quoting issue in precommit args

Author: adrn

.pre-commit-config.yaml

@@ -15,4 +15,4 @@ repos:
     rev: 0.5.0
     hooks:
     -   id: nbstripout
-        args: ["--extra-keys='metadata.kernelspec metadata.language_info.version metadata.toc'"]
+        args: ["--extra-keys=metadata.kernelspec metadata.language_info.version metadata.toc"]