Add db.system to the span data for mongo db.

sentry_sdk/integrations/pymongo.py

@@ -119,10 +119,11 @@ def started(self, event):
             except TypeError:
                 pass
 
-            data = {"operation_ids": {}}  # type: Dict[str, Dict[str, Any]]
+            data = {"operation_ids": {}}  # type: Dict[str, Union[Dict[str, Any], str]]
 
             data["operation_ids"]["operation"] = event.operation_id
             data["operation_ids"]["request"] = event.request_id
+            data["db.system"] = "mongodb"
 
             try:
                 lsid = command.pop("lsid")["id"]

tests/integrations/pymongo/test_pymongo.py

@@ -55,6 +55,7 @@ def test_transactions(sentry_init, capture_events, mongo_server, with_pii):
         "net.peer.port": str(mongo_server.port),
     }
     for span in find, insert_success, insert_fail:
+        assert span["data"]["db.system"] == "mongodb"
         for field, value in common_tags.items():
             assert span["tags"][field] == value