patch 8.2.4853: CI with FreeBSD is a bit outdated

Problem:    CI with FreeBSD is a bit outdated.
Solution:   Use 12.3 instead of 12.1. (closes #10333)
diff --git a/src/version.c b/src/version.c
index b03e661..de2ca4e 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4853,
+/**/
     4852,
 /**/
     4851,