Update requirements.txt

Author: pmasl

samples/development-frameworks/django/requirements.txt

@@ -4,7 +4,7 @@ dj-static==0.0.6
 gunicorn==19.6.0
 Unipath==1.0
 python-decouple==3
-Pillow==3.3.2
+Pillow>=8.2.0
 Markdown==2.6.6
 bleach>=3.3.0
 django-pyodbc-azure==1.9.6.0