Minor updates to deployment docs (#4184)

* Add last_status_change to api response
* link Canary Deployments to docs-dev-guide

Author: sethboyles

docs/v3/source/includes/api_resources/_deployments.erb

@@ -6,7 +6,8 @@
     "value": "ACTIVE",
     "reason": "DEPLOYING",
     "details": {
-      "last_successful_healthcheck": "2018-04-25T22:42:10Z"
+      "last_successful_healthcheck": "2018-04-25T22:42:10Z",
+      "last_status_change": "2018-04-25T22:42:10Z"
     }
   },
   "strategy": "canary",
@@ -80,7 +81,11 @@
       "guid": "59c3d133-2b83-46f3-960e-7765a129aea4",
       "status": {
         "value": "FINALIZED",
-        "reason": "DEPLOYED"
+        "reason": "DEPLOYED",
+        "details": {
+          "last_successful_healthcheck": "2018-04-25T22:42:10Z",
+          "last_status_change": "2018-04-25T22:42:10Z"
+        }
       },
       "strategy": "rolling",
       "options" : {

docs/v3/source/includes/resources/deployments/_header.md

@@ -16,4 +16,4 @@ Deployment strategies supported:
 applications to be deployed without incurring downtime by gradually rolling out instances. Max-in-flight can be configured
 to specify how many instances are rolled out simultaneously.
 
-* Canary deployments deploy a single instance and pause for user evaluation. If the canary instance is deemed successful, the deployment can be resumed via the [continue action](#continue-a-deployment). The deployment then continues like a rolling deployment. This feature is experimental and is subject to change.
+* [Canary deployments](https://docs.cloudfoundry.org/devguide/deploy-apps/rolling-deploy.html#canary-deployment-process) deploy a single instance and pause for user evaluation. If the canary instance is deemed successful, the deployment can be resumed via the [continue action](#continue-a-deployment). The deployment then continues like a rolling deployment. This feature is experimental and is subject to change.