Clarify watcher action uses PagerDuty API v2

x-pack/docs/en/watcher/actions/pagerduty.asciidoc

@@ -77,6 +77,8 @@ payload as well as an array of contexts to the action.
                             The account needs a `service_api_key` attribute.
 |======
 
+NOTE: Although some of the attributes below have names which match the PagerDuty "Events API v1" parameter
+      names, the "Events API v2" API is finally used by translating the attributes appropriately.
 
 [[pagerduty-event-trigger-incident-attributes]]
 .Pagerduty event trigger incident attributes
@@ -142,14 +144,9 @@ the PagerDuty service you want to send notifications to. To get the
 key:
 
 . Log in to http://pagerduty.com[pagerduty.com] as an account administrator.
-. Go to **Configuration > Services** and select the PagerDuty service. The 
-service must use the API integration.
-+
-image::images/pagerduty-services.jpg[]
-
-. Click the **Integrations** tab and copy the API integration key.
-+
-image::images/pagerduty-integrations.jpg[]
+. Go to **Services** and select the PagerDuty service you wish to target.
+. Click the **Integrations** tab and add an **Events API V2** integration if one does not already exist.
+. Copy the API integration key for use below.
 
 To configure a PagerDuty account in the keystore, you
 must specify an account name and integration key, (see <<secure-settings>>):