Bump certifi in /examples/reservations-bot-demo/cloud_function

Bumps [certifi](https://github.com/certifi/python-certifi) from 2020.6.20 to 2024.7.4.
- [Commits](certifi/python-certifi@2020.06.20...2024.07.04)

---
updated-dependencies:
- dependency-name: certifi
  dependency-version: 2024.7.4
  dependency-type: direct:production
...

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

Author: dependabot[bot]

examples/reservations-bot-demo/cloud_function/requirements.txt

@@ -1,4 +1,4 @@
-certifi==2020.6.20
+certifi==2024.7.4
 cffi==1.14.2
 chardet==3.0.4
 cryptography==48.0.1