patch 8.1.1091: MS-Windows: cannot use multi-byte chars in environment var

Problem:    MS-Windows: cannot use multi-byte chars in environment var.
Solution:   Use the wide API. (Ken Takata, closes #4008)
diff --git a/src/version.c b/src/version.c
index 0f62b83..c9987d2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -776,6 +776,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1091,
+/**/
     1090,
 /**/
     1089,