use GAR instead of GCR for updater image

- GCR is being deprecated and the updater stored there is no longer being updated
- Added the new secret to access the GAR updater image
- Updated image URL to point to the new GAR registry instead of GCR

.drone/drone.yml

@@ -1152,7 +1152,7 @@ depends_on:
 - Publish Linux agentctl container
 - Publish Linux agent-operator container
 image_pull_secrets:
-- dockerconfigjson
+- dockerconfigjson_gar
 kind: pipeline
 name: Deploy to deployment_tools
 platform:
@@ -1165,7 +1165,7 @@ steps:
   - echo "grafana/agent:$(sh ./tools/image-tag)" > .image-tag
   image: alpine
   name: Create .image-tag
-- image: us.gcr.io/kubernetes-dev/drone/plugins/updater
+- image: us-docker.pkg.dev/grafanalabs-global/docker-deployment-tools-prod/updater
   name: Update deployment_tools
   settings:
     config_json: |
@@ -1320,6 +1320,12 @@ get:
 kind: secret
 name: dockerconfigjson
 ---
+get:
+  name: .dockerconfigjson
+  path: secret/data/common/gar
+kind: secret
+name: dockerconfigjson_gar
+---
 get:
   name: .dockerconfigjson
   path: infra/data/ci/gcr-admin

.drone/pipelines/publish.jsonnet

@@ -96,7 +96,7 @@ linux_containers_jobs + windows_containers_jobs + [
     trigger: {
       ref: ['refs/heads/main'],
     },
-    image_pull_secrets: ['dockerconfigjson'],
+    image_pull_secrets: ['dockerconfigjson_gar'],
     steps: [
       {
         name: 'Create .image-tag',
@@ -109,7 +109,7 @@ linux_containers_jobs + windows_containers_jobs + [
       },
       {
         name: 'Update deployment_tools',
-        image: 'us.gcr.io/kubernetes-dev/drone/plugins/updater',
+        image: 'us-docker.pkg.dev/grafanalabs-global/docker-deployment-tools-prod/updater',
         settings: {
           config_json: |||
             {

.drone/util/secrets.jsonnet

@@ -11,6 +11,7 @@ local newSecret(name) = {
 
 {
   dockerconfigjson: newSecret('dockerconfigjson').getFrom(path='secret/data/common/gcr', name='.dockerconfigjson'),
+  dockerconfigjson_gar: newSecret('dockerconfigjson_gar').getFrom(path='secret/data/common/gar', name='.dockerconfigjson'),
   gcr_admin: newSecret('gcr_admin').getFrom(path='infra/data/ci/gcr-admin', name='.dockerconfigjson'),
 
   // Agent Github App