Update unstable library feature list by Travis CI build 1550

Author: Travis CI

unstable_library_feature.txt

@@ -124,7 +124,7 @@ unchecked_math                      none     2020-02-18 13:18:33 -0500  2020-02-
 can_vector                          69941    2020-03-11 18:02:52 -0700  2020-03-11 18:02:52 -0700
 option_zip                          70086    2020-03-18 11:02:29 +0300  2020-03-18 11:02:29 +0300
 result_flattening                   70142    2020-03-19 09:57:37 +0100  2020-03-19 09:57:37 +0100
-wake_trait                          69912    2020-03-23 01:36:08 +0100  2020-03-23 01:36:08 +0100
+wake_trait                          69912    2020-03-23 01:35:01 +0100  2020-03-23 01:35:01 +0100
 alloc_layout_extra                  55724    2020-03-24 11:45:38 +0100  2020-03-24 11:45:38 +0100
 osstring_ascii                      70516    2020-03-28 19:23:49 -0400  2020-03-28 19:23:49 -0400
 write_all_vectored                  70436    2020-03-31 15:16:43 +0200  2020-03-31 15:16:43 +0200