trigger docker image update after images have been pushed

Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
Change-Id: Id9c1cca84e9d058acdde6065249f88e2d047d142
diff --git a/ci-dockerfiles-deployment.yaml b/ci-dockerfiles-deployment.yaml
index 617b4d0..2644dab 100644
--- a/ci-dockerfiles-deployment.yaml
+++ b/ci-dockerfiles-deployment.yaml
@@ -68,5 +68,7 @@
         - shell:
             !include-raw: ci-dockerfiles-deployment/publish.sh
     publishers:
+        - trigger:
+            project: 'ci-dockerslaves-cleanup'
         - email:
             recipients: linaro-infrastructure-errors@lists.linaro.org