Clarify watcher action uses PagerDuty API v2 (#90800)

Add a note to help avoid the confusion stemming from the fact that the watcher attributes
still have names which seem to match the PagerDuty Events API v1 despite the fact that we are
actually now using v2 of that API.

Delete outdated screenshots

Co-authored-by: Iraklis Psaroudakis <kingherc@gmail.com>

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>>):