Bump nbconvert from 6.0.1 to 6.3.0 in /examples/research_projects/lxm…

…ert (huggingface#18565)

Bumps [nbconvert](https://github.com/jupyter/nbconvert) from 6.0.1 to 6.3.0.
- [Release notes](https://github.com/jupyter/nbconvert/releases)
- [Commits](jupyter/nbconvert@6.0.1...6.3.0)

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

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

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

examples/research_projects/lxmert/requirements.txt

@@ -43,7 +43,7 @@ matplotlib==3.3.1
 mistune==2.0.3
 msgpack==0.6.2
 nbclient==0.5.0
-nbconvert==6.5.1
+nbconvert==6.3.0
 nbformat==5.0.7
 nest-asyncio==1.4.0
 notebook==6.4.12