Bump pytz from 2023.3.post1 to 2024.1 in /backend

Bumps [pytz](https://github.com/stub42/pytz) from 2023.3.post1 to 2024.1.
- [Release notes](https://github.com/stub42/pytz/releases)
- [Commits](stub42/pytz@release_2023.3.post1...release_2024.1)

---
updated-dependencies:
- dependency-name: pytz
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

backend/requirements.txt

@@ -22,7 +22,7 @@ pytest-mock==3.12.0
 pytest-sqlalchemy-mock==0.1.5
 python-dotenv==1.0.1
 python-json-logger==2.0.7
-pytz==2023.3.post1
+pytz==2024.1
 PyYAML==6.0.1
 requests==2.31.0
 requests-mock==1.11.0