Fix Column View Python impl: sorting in year column

Author: rolandlo

src/Column View/main.py

@@ -28,8 +28,8 @@ def title(self) -> str:
     def author(self) -> str:
         return self._author
 
-    @GObject.Property(type=str)
-    def year(self) -> str:
+    @GObject.Property(type=int)
+    def year(self) -> int:
         return self._year