ci-dockerfiles-sanity-check: Switch node to build-amd64-private

To be able to access S3 buckets.

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: Ib4c84ed2c50e57e269aaf73c830413c2fdb40dda
diff --git a/ci-dockerfiles-sanity-check.yaml b/ci-dockerfiles-sanity-check.yaml
index f7b2378..f51e4e0 100644
--- a/ci-dockerfiles-sanity-check.yaml
+++ b/ci-dockerfiles-sanity-check.yaml
@@ -19,7 +19,7 @@
               - "ci-docker*"
             block-level: 'NODE'
     disabled: false
-    node: build-amd64
+    node: build-amd64-private
     concurrent: false
     display-name: 'CI Dockerfiles sanity check'
     parameters: