Update alerta docker image

PROD-37298

Change-Id: I65ebbd6b8608f120fb444c5aa5a8eaea1ff01891
diff --git a/defaults/docker_images.yml b/defaults/docker_images.yml
index 7282dda..89ea50a 100644
--- a/defaults/docker_images.yml
+++ b/defaults/docker_images.yml
@@ -1,7 +1,7 @@
 parameters:
   _param:
     # docker-prod-local.docker.mirantis.net/mcp/alerta:7.4.4-xenial-1692348098527
-    docker_image_alerta_tag: "2019.2.26"
+    docker_image_alerta_tag: "2019.2.27"
     docker_image_alertmanager_tag: "2019.2.26"
     docker_image_aptly_base_tag: "2019.2.26"
     docker_image_aptly_public_tag: "2019.2.26"