Bump notebook in /examples/research_projects/lxmert (#17743)

Bumps [notebook](http://jupyter.org

) from 6.4.10 to 6.4.12.

---
updated-dependencies:
- dependency-name: notebook
  dependency-type: direct:production
...
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examples/research_projects/lxmert/requirements.txt

@@ -46,7 +46,7 @@ nbclient==0.5.0
 nbconvert==6.0.1
 nbformat==5.0.7
 nest-asyncio==1.4.0
-notebook==6.4.10
+notebook==6.4.12
 numpy==1.21.0
 opencv-python==4.4.0.42
 packaging==20.3