bpo-27585: Add a NEWS entry for #1031 (#2036)

diff --git a/Misc/NEWS b/Misc/NEWS
index a8aff86..c013639 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -350,6 +350,9 @@
 Library
 -------
 
+- bpo-27585: Fix waiter cancellation in asyncio.Lock.
+  Patch by Mathieu Sornay.
+
 - bpo-30014: modify() method of poll(), epoll() and devpoll() based classes of
   selectors module is around 10% faster.  Patch by Giampaolo Rodola'.