[vulnerability] in example deps fix
Takes care of:
https://github.com/huggingface/transformers/security/dependabot/examples/research_projects/lxmert/requirements.txt/jinja2/open

@LysandreJik

Ah actually the dependabot PR was earlier in my notifications so I merged it without seeing you had opened a PR here. Sorry about that, closing as already taken care of in https://github.com/huggingface/transformers/commit/dbfe3795147e1360b3afac53a9ee0e14374d2ea6<|||||>Actually, the proposed `>=` is probably better, so fixing conflicts and merging this. Thanks @stas00!