chore(deps): bump notebook from 6.4.0 to 6.4.1 in /docs

Bumps [notebook](http://jupyter.org) from 6.4.0 to 6.4.1.

---
updated-dependencies:
- dependency-name: notebook
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

docs/requirements.txt

@@ -48,7 +48,7 @@ traitlets==5.0.5
 typing-extensions==3.10.0.0
 wcwidth==0.2.5
 zipp==3.4.1
-notebook==6.4.0
+notebook==6.4.1
 colorama==0.4.4
 asyncio==3.4.3
 pytest==6.2.4