patch 8.2.5081: autocmd test fails on MS-Windows

Problem:    Autocmd test fails on MS-Windows.
Solution:   Set shellslash to get forward slashes.
diff --git a/src/version.c b/src/version.c
index 20ca4eb..117a432 100644
--- a/src/version.c
+++ b/src/version.c
@@ -735,6 +735,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    5081,
+/**/
     5080,
 /**/
     5079,