test(fw): add headers to mock in test_git_reference_spec

Author: danceratopz

src/ethereum_test_base_types/tests/test_reference_spec.py

@@ -62,7 +62,7 @@
 def test_git_reference_spec(monkeypatch):
     """Test Git reference spec."""
 
-    def mock_get(self):
+    def mock_get(self, headers=None):
         class Response:
             content = (
                 '{"content": "'