patch 8.1.0031: terminal test aucmd_on_close if flaky

Problem:    Terminal test aucmd_on_close if flaky.
Solution:   Wait a bit longer.
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index 41a0a45..3d06eb3 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -384,7 +384,8 @@
 func s:get_sleep_cmd()
   if s:python != ''
     let cmd = s:python . " test_short_sleep.py"
-    let waittime = 500
+    " 500 was not enough for Travis
+    let waittime = 900
   else
     echo 'This will take five seconds...'
     let waittime = 2000
diff --git a/src/version.c b/src/version.c
index d13bcfd..846ac70 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    31,
+/**/
     30,
 /**/
     29,