patch 8.1.0752: one more compiler warning for signed/unsigned string

Problem:    One more compiler warning for signed/unsigned string. (Tony
            Mechelynck)
Solution:   Remove type cast.
diff --git a/src/version.c b/src/version.c
index f84da1d..2930e75 100644
--- a/src/version.c
+++ b/src/version.c
@@ -796,6 +796,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    752,
+/**/
     751,
 /**/
     750,