tf-m-extra-build: Triggered nightly and inform results by email

Job tf-m-extra-build is triggered nightly.
Results are reported to users by email.

Signed-off-by: Xinyu Zhang <xinyu.zhang@arm.com>
Change-Id: Ib82fe9fb76922004ebd26a38c47cd40715303e91
diff --git a/tf-m-extra-build.yaml b/tf-m-extra-build.yaml
index ee550d0..434a574 100644
--- a/tf-m-extra-build.yaml
+++ b/tf-m-extra-build.yaml
@@ -7,7 +7,7 @@
 
 - job:
     name: tf-m-extra-build
-    description: 'Build extra configurations.'
+    description: 'Build extra configurations nightly.'
     project-type: pipeline
     disabled: false
     sandbox: true
@@ -18,6 +18,8 @@
           num-to-keep: 45
       - authorization:
           !include: authorization.yaml.inc
+    triggers:
+      - timed: 'H 21 * * *'
     parameters:
       - string:
           name: 'FILTER_GROUP'
@@ -75,7 +77,7 @@
           description: "Name of Jenkins credential for authentication with LAVA."
       - string:
           name: 'EMAIL_NOTIFICATION'
-          default: ''
+          default: 'xinyu.zhang@arm.com'
       - string:
           name: 'SQUAD_CONFIGURATIONS'
           default: ''