Bump pillow from 5.3.0 to 6.2.0 in /utils/cli (#807)

Bumps [pillow](https://github.com/python-pillow/Pillow) from 5.3.0 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](https://github.com/python-pillow/Pillow/compare/5.3.0...6.2.0)

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

utils/cli/requirements.txt

@@ -1,2 +1,2 @@
-Pillow==5.3.0
+Pillow==6.2.0
 requests==2.20.1