[3.5.x] bump certifi

[vcidst]

Proposed changes:

• Bump certifi as per https://rasahq.atlassian.net/browse/ATO-1662

Status (please check what you already did):

• [ ] made PR ready for code review
• [ ] added some tests for the functionality
• [ ] updated the documentation in the rasaHQ/rasa
• [ ] updated the changelog (please check changelog for instructions)
• [ ] reformat files using black (please check Readme for instructions)

[vcidst]

@sanchariGr It looks like the CI is installing Poetry 1.2.2 here. Is this branch still maintained?