patch 8.1.0156: MS-Windows compiler warning

Problem:    MS-Windows compiler warning.
Solution:   Add a type cast. (Mike Williams)
diff --git a/src/version.c b/src/version.c
index 2be3ae1..63a7694 100644
--- a/src/version.c
+++ b/src/version.c
@@ -61,7 +61,7 @@
 		+ strlen(VIM_VERSION_DATE_ONLY)
 		+ strlen(date_time);
 
-    longVersion = (char *)alloc(len);
+    longVersion = (char *)alloc((unsigned)len);
     if (longVersion == NULL)
 	longVersion = VIM_VERSION_LONG;
     else
@@ -790,6 +790,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    156,
+/**/
     155,
 /**/
     154,