chore(deps): bump notebook from 6.1.6 to 6.4.1 (#52)

Bumps [notebook](http://jupyter.org) from 6.1.6 to 6.4.1.

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

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

requirements.txt

@@ -35,7 +35,7 @@ nbconvert==6.0.7
 nbformat==5.0.8
 nest-asyncio==1.4.3
 nltk==3.5
-notebook==6.1.6
+notebook==6.4.1
 numpy==1.19.5
 openpyxl==3.0.5
 packaging==20.8