Add RestFramework handler kwargs

Author: GeekMasher

python/ql/lib/semmle/python/frameworks/RestFramework.qll

@@ -194,6 +194,9 @@ private module RestFramework {
       exists(RestFrameworkApiViewClass vc |
         this.getParameter() =
           vc.getARequestHandler().(PrivateDjango::DjangoRouteHandler).getRequestParam()
+        or
+        // retrieve(self, request, **kwargs)
+        this.getParameter() = vc.getARequestHandler().(PrivateDjango::DjangoRouteHandler).getKwarg()
       )
       or
       // annotated with @api_view decorator