Log Message:
py-django3: updated to 3.1.5

Django 3.1.5 fixes several bugs in 3.1.4.

Fixed __isnull=True lookup on key transforms for JSONField with Oracle and SQLite.
Fixed a bug in Django 3.1 that caused a crash when processing middlewares in an \ 
async context with a middleware that raises a MiddlewareNotUsed exception.
Fixed a regression in Django 3.1 that caused the incorrect prefixing of \ 
STATIC_URL and MEDIA_URL settings, by the server-provided value of SCRIPT_NAME \ 
(or / if not set), when set to a URL specifying the protocol but without a \ 
top-level domain, e.g. http://myhost/