patch 8.1.0057: popup menu displayed wrong when using autocmd

Problem:    Popup menu displayed wrong when using autocmd.
Solution:   Use aucmd_prepbuf().  Force updating status line if the popup menu
            is going to be redrawn anyway. (Christian Brabandt, closes #3009)
diff --git a/src/version.c b/src/version.c
index bd8efaf..f4ecfe7 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    57,
+/**/
     56,
 /**/
     55,