tf-a-lts2.8-ci-gateway: Run tf-a-lts2.8-builder

https://linaro.atlassian.net/browse/TFC-450

Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Change-Id: I9babf9902c5ccf225bfc3fa4c2b53ed93ebbe509
diff --git a/tf-a-lts2.8-ci-gateway.yaml b/tf-a-lts2.8-ci-gateway.yaml
index 45d8f96..e24403f 100644
--- a/tf-a-lts2.8-ci-gateway.yaml
+++ b/tf-a-lts2.8-ci-gateway.yaml
@@ -85,7 +85,7 @@
         EOF
     - trigger-builds:
       - project:
-        - tf-a-builder
+        - tf-a-lts2.8-builder
         block: true
         property-file: share.param
         current-parameters: true