⬆️ Bump pytz from 2020.4 to 2021.1 in /backend/uclapi (#3136)

Bumps [pytz](https://github.com/stub42/pytz) from 2020.4 to 2021.1.
- [Release notes](https://github.com/stub42/pytz/releases)
- [Commits](stub42/pytz@release_2020.4...release_2021.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Ethan Wood <5961364+greenfrogs@users.noreply.github.com>

backend/uclapi/requirements.txt

@@ -27,7 +27,7 @@ pycodestyle==2.6.0
 psycopg2-binary==2.8.6
 python-dateutil==2.8.1
 pymsteams==0.1.14
-pytz==2020.4
+pytz==2021.1
 raven==6.10.0
 redis==3.5.3
 requests==2.25.1