Add a new private version to the builtin dict type

Issue #26058: Add a new private version to the builtin dict type, incremented
at each dictionary creation and at each dictionary change.

Implementation of the PEP 509.
diff --git a/Include/dictobject.h b/Include/dictobject.h
index 02d40ff..19194ed 100644
--- a/Include/dictobject.h
+++ b/Include/dictobject.h
@@ -26,6 +26,10 @@
     /* Number of items in the dictionary */
     Py_ssize_t ma_used;
 
+    /* Dictionary version: globally unique, value change each time
+       the dictionary is modified */
+    uint64_t ma_version_tag;
+
     PyDictKeysObject *ma_keys;
 
     /* If ma_values is NULL, the table is "combined": keys and values