patch 8.0.0595: Coverity warning for not checking return value

Problem:    Coverity warning for not checking return value of dict_add().
Solution:   Check the return value for FAIL.
diff --git a/src/version.c b/src/version.c
index 6e2620d..8895b73 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    595,
+/**/
     594,
 /**/
     593,