Slack alerts for integration test suite (#2615)

* Notify Slack on integration test failure

* Run integration tests on most recent minors

* Whoops, wrong alpha

Author: JoshMock

catalog-info.yaml

@@ -28,6 +28,9 @@ spec:
     spec:
       repository: elastic/elasticsearch-js
       pipeline_file: .buildkite/pipeline.yml
+      env:
+        ELASTIC_SLACK_NOTIFICATIONS_ENABLED: "true"
+        SLACK_NOTIFICATIONS_CHANNEL: "#devtools-notify-javascript"
       teams:
         devtools-team:
           access_level: MANAGE_BUILD_AND_READ
@@ -45,6 +48,9 @@ spec:
         8_x:
           branch: "8.x"
           cronline: "@daily"
-        8_14:
-          branch: "8.16"
+        8_17:
+          branch: "8.17"
+          cronline: "@daily"
+        8_18:
+          branch: "8.18"
           cronline: "@daily"