Bump pillow from 5.1.0 to 8.1.1 in /django_auth_example

Bumps [pillow](https://github.com/python-pillow/Pillow) from 5.1.0 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@5.1.0...8.1.1)

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

Author: dependabot[bot]

django_auth_example/requirements.txt

@@ -118,7 +118,7 @@ patsy==0.5.0
 pep8==1.7.1
 pexpect==4.5.0
 pickleshare==0.7.4
-Pillow==5.1.0
+Pillow==8.1.1
 pkginfo==1.4.2
 pluggy==0.6.0
 ply==3.11