patch 8.2.0652: compiler warning for char conversion

Problem:    Compiler warning for char conversion.
Solution:   Use unsigned char buffer.
diff --git a/src/version.c b/src/version.c
index 6542b37..f9951e9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    652,
+/**/
     651,
 /**/
     650,