ci(pipeline): specify main branch in helm-charts repository

- Specified 'main' as the reference branch for the helm-charts repository in the pipeline configuration.

Author: winromulus

.github/workflows/pipeline.yaml

@@ -129,6 +129,7 @@ jobs:
           repository: emberstack/helm-charts
           token: ${{ secrets.ES_GITHUB_PAT }}
           path: helm-charts
+          ref: main
 
       - name: github - publish - chart
         run: |