Fix import issue

Signed-off-by: Tushar Goel <tushar.goel.dav@gmail.com>

Author: TG1999

vulnerabilities/importer.py

@@ -111,7 +111,7 @@ def to_dict(self):
     def from_dict(cls, ref: dict):
         return cls(
             reference_id=ref["reference_id"],
-            reference_type=ref["reference_type"],
+            reference_type=ref.get("reference_type") or "",
             url=ref["url"],
             severities=[
                 VulnerabilitySeverity.from_dict(severity) for severity in ref["severities"]