Bump pillow from 6.2.0 to 7.1.0

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>

requirements.txt

@@ -3,4 +3,4 @@ numpy==1.16.4
 opencv-python==4.1.1.26
 paddlehub==1.6.0
 paddlepaddle==1.7.2
-Pillow==6.2.0
+Pillow==7.1.0