CI change - incorporates PR #1 against ndmckinley/github-pullrequest-resource. (GoogleCloudPlatform#1131)

Merged PR GoogleCloudPlatform#1131.

Author: nat-henderson

.ci/ci.yml.tmpl

@@ -20,7 +20,7 @@ resource_types:
       type: docker-image
       source:
           repository: nmckinley/concourse-github-pr-resource
-          tag: v0.1.16
+          tag: v0.1.17
 
 resources:
     - name: magic-modules