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](stub42/pytz@release_2020.5...release_2021.1)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

docs-requirements.txt

@@ -28,7 +28,7 @@ pygments==2.7.4
     # via sphinx
 pyparsing==2.4.7
     # via packaging
-pytz==2020.5
+pytz==2021.1
     # via babel
 requests==2.25.1
     # via sphinx

test-requirements.txt

@@ -54,7 +54,7 @@ pytest==6.2.2
     # via
     #   -r test-requirements.in
     #   pytest-cov
-pytz==2020.5
+pytz==2021.1
     # via babel
 requests==2.25.1
     # via sphinx