Bump pillow from 3.4.2 to 6.2.0 in /examples/requirements

Bumps [pillow](https://github.com/python-pillow/Pillow) from 3.4.2 to 6.2.0.
- [Release notes](https://github.com/python-pillow/Pillow/releases)
- [Changelog](https://github.com/python-pillow/Pillow/blob/master/CHANGES.rst)
- [Commits](python-pillow/Pillow@3.4.2...6.2.0)

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

examples/requirements/testing.txt

@@ -1,7 +1,7 @@
 beautifulsoup4==4.5.1
 factory_boy==2.11.1
 Faker==1.0.4
-Pillow==3.4.2
+Pillow==6.2.0
 pytest-cov==2.6.1
 pytest-django==3.4.8
 pytest==4.4.0