Enable CQ stale tryjob cancellation.

Tryjobs for old patchsets will be cancelled when a newer one is uploaded.

Bug: chromium:909895
Change-Id: I8ca1066ee5674fcde0839d8c4b9e22c6050d92cf
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/147863
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Oleh Prypin <oprypin@webrtc.org>
diff --git a/commit-queue.cfg b/commit-queue.cfg
index 70a238c..7a70fac 100644
--- a/commit-queue.cfg
+++ b/commit-queue.cfg
@@ -196,6 +196,7 @@
         transient_failure_weight: 1
         timeout_weight: 2
       >
+      cancel_stale_tryjobs: YES
     >
   >
 >
@@ -365,6 +366,7 @@
         transient_failure_weight: 1
         timeout_weight: 2
       >
+      cancel_stale_tryjobs: YES
     >
   >
 >
@@ -392,6 +394,7 @@
         transient_failure_weight: 1
         timeout_weight: 2
       >
+      cancel_stale_tryjobs: YES
     >
   >
 >