Bump pytz from 2020.5 to 2021.1

Bumps [pytz](https://github.com/stub42/pytz) from 2020.5 to 2021.1.
- [Release notes](https://github.com/stub42/pytz/releases)
- [Commits](https://github.com/stub42/pytz/compare/release_2020.5...release_2021.1)

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

requirements.txt

@@ -1,6 +1,6 @@
 asgiref==3.3.1
 Django==3.1.7
-pytz==2020.5
+pytz==2021.1
 sqlparse==0.4.1
 requests
 python-slugify