patch 9.0.1448: diff test fails on MacOS 13

Problem:    Diff test fails on MacOS 13.
Solution:   Install GNU diffutils. (Ozaki Kiichi, closes #12258)
diff --git a/src/version.c b/src/version.c
index 60de2bb..ba8b40e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1448,
+/**/
     1447,
 /**/
     1446,