Bump certifi from 2016.9.26 to 2022.12.7 in /app

Bumps [certifi](https://github.com/certifi/python-certifi) from 2016.9.26 to 2022.12.7.
- [Release notes](https://github.com/certifi/python-certifi/releases)
- [Commits](https://github.com/certifi/python-certifi/compare/2016.09.26...2022.12.07)

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

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

app/requirements.txt

@@ -1,6 +1,6 @@
 backports-abc==0.4
 bokeh==0.10.0
-certifi==2016.9.26
+certifi==2022.12.7
 click==6.6
 flask>=1.0.0
 Flask-SocketIO==2.7.1