Change node name from master to built-in [1]

[1]: https://www.jenkins.io/doc/book/managing/built-in-node-migration/

Signed-off-by: Arthur She <arthur.she@linaro.org>
Change-Id: Ic89d5243705365ad6d006c0cecf7818bbd5dd50a
diff --git a/ci-job-configs-sanity-check.yaml b/ci-job-configs-sanity-check.yaml
index 1b61f6a..e42bba3 100644
--- a/ci-job-configs-sanity-check.yaml
+++ b/ci-job-configs-sanity-check.yaml
@@ -12,7 +12,7 @@
             days-to-keep: 30
             num-to-keep: 30
     disabled: false
-    node: master
+    node: built-in
     display-name: 'CI job configs sanity check'
     scm:
         - git:
diff --git a/trigger-ci-job-configs.yaml b/trigger-ci-job-configs.yaml
index ad2e02e..e5dad58 100644
--- a/trigger-ci-job-configs.yaml
+++ b/trigger-ci-job-configs.yaml
@@ -14,7 +14,7 @@
             days-to-keep: 30
             num-to-keep: 200
     disabled: false
-    node: master
+    node: built-in
     display-name: 'CI job configs deployment'
     scm:
         - git: