Subscribe to Workstation App pr merges

This change attempts to subscribe to merge events
on chef/chef-workstation-app and use that to manage
our dependency on the project.

Signed-off-by: Jon Morrow <jmorrow@chef.io>

.expeditor/config.yml

@@ -43,3 +43,6 @@ subscriptions:
   - workload: artifact_published:stable:chefdk:3*
     actions:
       - bash:.expeditor/update_chefdk_to_stable.sh
+  - workload: pull_request_merged:chef/chef-workstation-app:master:*
+    actions:
+      - bash:.expeditor/update_chef-workstation-app_to_latest.sh

.expeditor/update_chef-workstation-app_to_latest.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+############################################################################
+# What is this script?
+#
+# Chef Workstation uses Expeditor to manage the bundled version of the
+# Chef Workstation App. Currently we always want to include the latest version 
+# of Chef Workstation App inside Workstation, so this script takes that version
+# and uses sed to insert it into the omnibus project definition. Then it commits
+# that change and opens a pull request for review and merge.
+############################################################################
+
+set -evx
+
+version=$(get_github_file $SCM_SETTINGS_GITHUB_REPO master VERSION)
+
+branch="expeditor/chef_workstation_app_${version}"
+git checkout -b "$branch"
+
+sed -i -r "s/override :\"chef-workstation-app\",\s+version: \"v[^\"]+\"/override :\"chef-workstation-app\", version: \"v${version}\"/" omnibus/config/projects/chef-workstation.rb
+
+git add .
+
+# give a friendly message for the commit and make sure it's noted for any future audit of our codebase that no
+# DCO sign-off is needed for this sort of PR since it contains no intellectual property
+git commit --message "Bump Chef Workstation App to $version" --message "This pull request was triggered automatically via Expeditor when Chef Workstation App $version was merged." --message "This change falls under the obvious fix policy so no Developer Certificate of Origin (DCO) sign-off is required."
+
+open_pull_request
+
+# Get back to master and cleanup the leftovers - any changed files left over at the end of this script will get committed to master.
+git checkout -
+git branch -D "$branch"

omnibus/config/projects/chef-workstation.rb

@@ -51,6 +51,12 @@
 
 override :"chef-dk", version: "v3.3.23"
 
+# The Chef Workstation App version is pinned by Expeditor. Whenever Chef Workstation
+# App is merged then Expeditor takes the latest tag, runs a script to replace it here
+# and pushes a new commit / build through.
+
+override :"chef-workstation-app", version: "v3.3.23"
+
 # DK's overrides; god have mercy on my soul
 # This comes from DK's ./omnibus_overrides.rb
 # If this stays, may need to duplicate that file and the rake