Bump nbconvert from 5.6.1 to 6.5.1 in /Otherfiles

Bumps [nbconvert](https://github.com/jupyter/nbconvert) from 5.6.1 to 6.5.1.
- [Release notes](https://github.com/jupyter/nbconvert/releases)
- [Changelog](https://github.com/jupyter/nbconvert/blob/main/CHANGELOG.md)
- [Commits](jupyter/nbconvert@5.6.1...6.5.1)

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

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

Otherfiles/doc-requirements.txt

@@ -2,7 +2,7 @@ art==6.3
 notebook==5.7.4
 nbformat==5.0.8
 traitlets==4.3.3
-nbconvert==5.6.1
+nbconvert==6.5.1
 jupyter_contrib_nbextensions==0.5.1
 MarkupSafe==2.0.1
 jinja2==2.10.1