re-added get_version with deprecation

unified_planning/model/problem_kind.py

@@ -16,6 +16,7 @@
 from functools import cache, partialmethod, total_ordering
 from itertools import chain
 from typing import Dict, Iterable, List, Optional, Set
+from warnings import warn
 import unified_planning as up
 
 from unified_planning.model.problem_kind_versioning import (
@@ -279,6 +280,10 @@ def version(self) -> int:
         ), "Calculated version is > that the LATEST declared version"
         return max_version
 
+    def get_version(self) -> Optional[int]:
+        warn(DeprecationWarning("Use version property instead."))
+        return self.version
+
     def union(self, oth: "ProblemKind") -> "ProblemKind":
         """
         Returns a new `ProblemKind` that is the union of this `ProblemKind` and