patch 8.0.1456: timer test on travis Mac is still flaky

Problem:    Timer test on travis Mac is still flaky.
Solution:   Increase time range a bit more.
diff --git a/src/testdir/test_timers.vim b/src/testdir/test_timers.vim
index 55f5245..df42b2c 100644
--- a/src/testdir/test_timers.vim
+++ b/src/testdir/test_timers.vim
@@ -124,7 +124,7 @@
   if has('reltime')
     if has('mac')
       " The travis Mac machines appear to be very busy.
-      call assert_inrange(0, 40, slept)
+      call assert_inrange(0, 50, slept)
     else
       call assert_inrange(0, 30, slept)
     endif
diff --git a/src/version.c b/src/version.c
index 69ba3f5..bb43796 100644
--- a/src/version.c
+++ b/src/version.c
@@ -772,6 +772,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1456,
+/**/
     1455,
 /**/
     1454,