Support parsing of multipart/form-data post bodies

[beniwohli]

We currently are not able to parse form data if it is encoded as multipart/form-data.

[daikeren]

I would like to try to fix this issue since I need the feature. Could I fix the issue by modified the code
https://github.com/opbeat/opbeat_python/blob/master/opbeat/contrib/django/client.py#L85-L110

here?
Thanks.

[beniwohli]

@daikeren sorry for the delay. Yes, that would indeed be the place to fix the problem. It might make sense to piggy back on Django's parsing of multipart/form-data (used here: https://github.com/django/django/blob/master/django/http/request.py#L271)