patch 9.1.0668: build-error with python3.12 and stable ABI

Problem:  build-error with python3.12 and stable ABI (zdohnal)
Solution: Add type casts, define Py_INCREF for Python3.12 and higher
          (Ken Takata)

fixes: #15460

Signed-off-by: Ken Takata <kentkt@csc.jp>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 444a1b2..965a20d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    668,
+/**/
     667,
 /**/
     666,