chore: fix type checking and CI workflow (#2)

ghaw_auditor/parser.py

@@ -157,7 +157,7 @@ class Parser:
         actions_used: list[ActionRef] = []
         secrets_used: set[str] = set()
 
-        if is_reusable_call:
+        if is_reusable_call and isinstance(uses, str):
             # Parse reusable workflow reference
             workflow_ref = self._parse_reusable_workflow_ref(uses, path)
             actions_used.append(workflow_ref)