Bug 2006580 - ci: migrate decision task to d2g worker pool (#334)

Author: jcristau

.taskcluster.yml

@@ -155,7 +155,7 @@ tasks:
                                         name: "Decision Task for cron job ${cron.job_name}"
                                         description: 'Created by a [cron task](https://tools.taskcluster.net/tasks/${cron.task_id})'
                       provisionerId: "xpi-${level}"
-                      workerType: "decision-gcp"
+                      workerType: "decision"
                       tags:
                           $if: 'tasks_for in ["github-push", "github-pull-request"]'
                           then: