Bump notebook from 6.1.5 to 6.4.12

Bumps [notebook](http://jupyter.org) from 6.1.5 to 6.4.12.

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

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

Author: dependabot[bot]

requirements.txt

@@ -33,7 +33,7 @@ mistune==0.8.4
 mizani==0.5.4
 nbconvert==5.5.0
 nbformat==4.4.0
-notebook==6.1.5
+notebook==6.4.12
 numpy==1.22.0
 packaging==19.1
 palettable==3.2.0