Bump pillow from 7.1.2 to 8.1.1

Bumps [pillow](https://github.com/python-pillow/Pillow) from 7.1.2 to 8.1.1.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst)
- [Commits](python-pillow/Pillow@7.1.2...8.1.1)

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

Author: dependabot[bot]

setup.py

@@ -37,7 +37,7 @@
         'Django==2.2.13',
         'docutils==0.15.2',
         'netaddr==0.7.19',
-        'Pillow==7.1.2',
+        'Pillow==8.1.1',
         'psycopg2-binary==2.8.5',
         'redis==3.5.3',
         'requests==2.23.0',