patch 9.0.0733: use of strftime() is not safe

Problem:    Use of strftime() is not safe.
Solution:   Check the return value of strftime().  Use a larger buffer and
            correctly pass the available space. (Dominique Pellé, closes
            #11348)
diff --git a/src/version.c b/src/version.c
index 37d64fb..eeb1579 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    733,
+/**/
     732,
 /**/
     731,