[IMP] packages: match PIL to debian version

https://packages.debian.org/buster/python-pil


As of today, python-pillow is at 5.4 in the latest debian release

This allows to deprecate the older versions progessively

Newer versions have new features like the exif_transpose method in 6.0
as discussed at #37448

closes odoo/odoo#38245

X-original-commit: 4ad7a99d
Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>

requirements.txt

@@ -20,7 +20,7 @@ mock==2.0.0
 num2words==0.5.6
 ofxparse==0.16
 passlib==1.6.5
-Pillow==4.0.0
+Pillow==5.4.0
 polib==1.1.0
 psutil==4.3.1; sys_platform != 'win32'
 psycopg2==2.7.3.1; sys_platform != 'win32'