Add luci-scheduler job for chromeos-amd64-generic-rel CI bot.

Bug: 793907
Change-Id: Id31acad64245e66741e0271941c55ea5d71986a1
Reviewed-on: https://chromium-review.googlesource.com/990582Reviewed-by: Nodir Turakulov <nodir@chromium.org>
Commit-Queue: Benjamin Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547573}

infra/config/global/luci-scheduler.cfg

@@ -66,6 +66,9 @@ trigger {
   triggers: "Android x86 Builder (dbg)"
   triggers: "Optional Android Release (Nexus 5X)"
 
+  # ChromeOS. Sorted alphabetically.
+  triggers: "chromeos-amd64-generic-rel"
+
   # Linux. Sorted alphabetically.
   triggers: "Cast Linux"
   triggers: "Deterministic Linux"
@@ -316,6 +319,19 @@ job {
   # }
 }
 
+################################################################################
+# ChromeOS Builders. Sorted alphabetically.
+################################################################################
+
+job {
+  id: "chromeos-amd64-generic-rel"
+  acl_sets: "default"
+  buildbucket: {
+    server: "cr-buildbucket.appspot.com"
+    bucket: "luci.chromium.ci"
+    builder: "chromeos-amd64-generic-rel"
+  }
+}
 
 ################################################################################
 # Linux Builders. Sorted alphabetically except builder-Testers must follow their