Merge pull request #1607 from OpenTechFund/dependabot/pip/pillow-6.2.1

[Security] Bump pillow from 5.4.1 to 6.2.1

requirements.txt

@@ -43,7 +43,7 @@ gunicorn==19.9.0
 mailchimp3==3.0.9
 mistune==0.8.4
 more-itertools==7.2.0
-Pillow==5.4.1
+Pillow==6.2.1
 psycopg2==2.7.3.1
 social_auth_app_django==3.1.0
 tomd==0.1.3