Fix version getter

Author: martinRenou

python/jupytercad_core/jupytercad_core/jcad_ydoc.py

@@ -20,6 +20,7 @@ def __init__(self, *args, **kwargs):
         self._ydoc["outputs"] = self._youtputs = Map()
         self.undo_manager.expand_scope(self._yobjects)
 
+    @property
     def version(self) -> str:
         return SCHEMA_VERSION
 

python/jupytercad_core/jupytercad_core/step_ydoc.py

@@ -13,6 +13,7 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self._ydoc["source"] = self._ysource = Text()
 
+    @property
     def version(self) -> str:
         return SCHEMA_VERSION
 

python/jupytercad_core/jupytercad_core/stl_ydoc.py

@@ -13,6 +13,7 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self._ydoc["source"] = self._ysource = Text()
 
+    @property
     def version(self) -> str:
         return SCHEMA_VERSION