Bump pillow from 6.2.0 to 7.1.0 in /examples

Bumps [pillow](https://github.com/python-pillow/Pillow) from 6.2.0 to 7.1.0. - [Release notes](https://github.com/python-pillow/Pillow/releases) - [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst) - [Commits](python-pillow/Pillow@6.2.0...7.1.0) Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

examples/requirements.txt

@@ -2,7 +2,7 @@ cssselect==1.0.1
 django-classy-tags==0.9.0
 django-sekizai==1.0.0
 easy-thumbnails==2.6.0
-Pillow==6.2.0
+Pillow==7.1.0
 pluggy==0.12.0
 py==1.8.0
 pytz==2019.3