Adding dev channel publish hab channel

Signed-off-by: nitin sanghi <[email protected]>

.expeditor/config.yml

@@ -8,6 +8,8 @@ slack:
 # This publish is triggered by the `built_in:publish_rubygems` artifact_action.
 rubygems:
   - ohai
+artifact_channels:
+  - dev
 
 github:
   # This deletes the GitHub PR branch after successfully merged into the release branch
@@ -73,4 +75,5 @@ subscriptions:
   - workload: buildkite_hab_build_group_published:{{agent_id}}:*
     actions:
       # when all of the hab package publish to the unstable channel, test and promote them
-      - trigger_pipeline:habitat/build-test
+      - trigger_pipeline:habitat/build-test
+      - built_in:promote_habitat_packages