Upgrade dependencies

requirements.txt

-oic==1.2.0
+oic==1.2.1
 pika==1.1.0
-urllib3==1.25.10
-Django==3.0.8
-djangorestframework==3.11.1
-django-cors-headers==3.4.0
-django-mysql==3.8.1
-django_polymorphic==2.1.2
+urllib3==1.26.2
+Django==3.1.4
+djangorestframework==3.12.2
+django-cors-headers==3.5.0
+django-mysql==3.9.0
+django_polymorphic==3.0.0
 django-rest-polymorphic==0.1.8
 mysqlclient==2.0.1
 PyJWT==1.7.1
-pytest==6.1.1
-pytest-django==4.0.0
+pytest==6.1.2
+pytest-django==4.1.0
 coverage==5.3
 ipython==7.16.1
 mixer==6.1.3