[Fix](Producer) Add ignore attribute to False by default

aidge_export_cpp/operators/Producer.py

@@ -47,7 +47,10 @@ class ProducerCPP(ExportNode):
     def __init__(self, node, mem_info):
         super().__init__(node, mem_info)
         self.values = np.array(self.operator.get_output(0))
-        self.ignore = node.attributes().ignore
+        if node.attributes().has_attr("ignore"):
+            self.ignore = node.attributes().ignore
+        else:
+            self.ignore = False
 
         if len(self.values.shape) == 4:  # Note: export in HWC
             self.values = np.transpose(self.values, (0, 2, 3, 1))