Bump nbconvert from 5.6.1 to 6.5.1

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

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

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

Author: dependabot[bot]

requirements.txt

@@ -38,7 +38,7 @@ mkl-random==1.1.0
 mkl-service==2.3.0
 more-itertools==7.2.0
 murmurhash==1.0.2
-nbconvert==5.6.1
+nbconvert==6.5.1
 nbformat==4.4.0
 networkx==2.4
 numpy==1.22.0