patch 8.1.0783: compiler warning for signed/unsigned

Problem:    Compiler warning for signed/unsigned.
Solution:   Add type cast.  Change type of buffer. (Ozaki Kiichi, closes #3827)
diff --git a/src/version.c b/src/version.c
index 6f8f874..11e4bb6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -792,6 +792,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    783,
+/**/
     782,
 /**/
     781,