Bump certifi from 2018.4.16 to 2022.12.7 in /examples/yoti_example_flask

Bumps [certifi](https://github.com/certifi/python-certifi) from 2018.4.16 to 2022.12.7.
- [Release notes](https://github.com/certifi/python-certifi/releases)
- [Commits](certifi/python-certifi@2018.04.16...2022.12.07)

---
updated-dependencies:
- dependency-name: certifi
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Diff for: examples/yoti_example_flask/requirements.txt

@@ -6,7 +6,7 @@
 #
 asn1==2.2.0
     # via yoti
-certifi==2018.4.16
+certifi==2022.12.7
     # via requests
 cffi==1.15.0
     # via