Added feature to specify a custom Auto DevOps chart repository

changelogs/unreleased/custom-helm-chart-repo.yml

+---
+title: Added feature to specify a custom Auto DevOps chart repository
+merge_request: 24162
+author: walkafwalka
+type: added

doc/topics/autodevops/index.md

@@ -609,7 +609,7 @@ repo or by specifying a project variable:
   one](https://gitlab.com/charts/auto-deploy-app).
   This can be a great way to control exactly how your application is deployed.
 - **Project variable** - Create a [project variable](../../ci/variables/README.md#variables)
-  `AUTO_DEVOPS_CHART` with the URL of a custom chart to use.
+  `AUTO_DEVOPS_CHART` with the URL of a custom chart to use or create two project variables `AUTO_DEVOPS_CHART_REPOSITORY` with the URL of a custom chart repository and `AUTO_DEVOPS_CHART` with the path to the chart.
 
 ### Customizing `.gitlab-ci.yml`
 

lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml

@@ -793,7 +793,7 @@ rollout 100%:
     fi
 
     helm init --client-only
-    helm repo add gitlab https://charts.gitlab.io
+    helm repo add gitlab ${AUTO_DEVOPS_CHART_REPOSITORY:-https://charts.gitlab.io}
     if [[ ! -d "$auto_chart" ]]; then
       helm fetch ${auto_chart} --untar
     fi