[monitoring] testing: start using build specific projects [(#3771)](GoogleCloudPlatform/python-docs-samples#3771)

Also added `required_api_url` and `required_role` field in `README.rst.in`.

A part of #3310 

Note: Now the service account has permission only on the project for py36 build, so py37 build should fail.

Author: Takashi Matsuo

samples/snippets/v3/alerts-client/README.rst

@@ -14,6 +14,13 @@ This directory contains samples for Google Stackdriver Alerting API. Stackdriver
 
 .. _Google Stackdriver Alerting API: https://cloud.google.com/monitoring/alerts/
 
+To run the sample, you need to enable the API at: https://console.cloud.google.com/apis/library/monitoring.googleapis.com
+
+To run the sample, you need to have `Monitoring Admin` role.
+
+Please visit [the Cloud Console UI of this API](https://console.cloud.google.com/monitoring) and [create a new Workspace with the same name of your Cloud project](https://cloud.google.com/monitoring/workspaces/create).
+
+
 Setup
 -------------------------------------------------------------------------------
 
@@ -87,7 +94,21 @@ To run this sample:
         list-alert-policies
         list-notification-channels
         enable-alert-policies
+                            Enable or disable alert policies in a project.
+                            Arguments: project_name (str) enable (bool): Enable or
+                            disable the policies. filter_ (str, optional): Only
+                            enable/disable alert policies that match this filter_.
+                            See
+                            https://cloud.google.com/monitoring/api/v3/sorting-
+                            and-filtering
         disable-alert-policies
+                            Enable or disable alert policies in a project.
+                            Arguments: project_name (str) enable (bool): Enable or
+                            disable the policies. filter_ (str, optional): Only
+                            enable/disable alert policies that match this filter_.
+                            See
+                            https://cloud.google.com/monitoring/api/v3/sorting-
+                            and-filtering
         replace-notification-channels
         backup
         restore
@@ -114,4 +135,4 @@ to `browse the source`_ and  `report issues`_.
     https://github.com/GoogleCloudPlatform/google-cloud-python/issues
 
 
-.. _Google Cloud SDK: https://cloud.google.com/sdk/
+.. _Google Cloud SDK: https://cloud.google.com/sdk/

samples/snippets/v3/alerts-client/README.rst.in

@@ -12,6 +12,13 @@ product:
       and many others. Stackdriver's Alerting API allows you to create,
       delete, and make back up copies of your alert policies.
 
+required_api_url: https://console.cloud.google.com/apis/library/monitoring.googleapis.com
+required_role: Monitoring Admin
+other_required_steps: >
+    Please visit [the Cloud Console UI of this
+    API](https://console.cloud.google.com/monitoring) and create a new
+    Workspace with the same name of your Cloud project.
+
 setup:
 - auth
 - install_deps
@@ -23,4 +30,4 @@ samples:
 
 cloud_client_library: true
 
-folder: monitoring/api/v3/alerts-client
+folder: monitoring/api/v3/alerts-client