Recognize Content Type ending with +json as JSON type

Sentry should recognize API JSON requests as JSON type not as Form. If they are recognized as Form the body payload appears empty in Sentry UI.
RFC6839: https://tools.ietf.org/html/rfc6839#page-4

Author: Iva Kaneva

raven/contrib/flask.py

@@ -193,7 +193,7 @@ def get_http_info(self, request):
         return self.get_http_info_with_retriever(request, retriever)
 
     def is_json_type(self, content_type):
-        return content_type == 'application/json'
+        return content_type == 'application/json' or content_type.endswith('+json')
 
     def get_form_data(self, request):
         return request.form