feat: auto-deploy-app version bump

Bumped auto-deploy-app version to 2.28.0

assets/auto-deploy-app/Chart.yaml

 apiVersion: v1
 description: GitLab's Auto-deploy Helm Chart
 name: auto-deploy-app
-version: 2.27.0
+version: 2.28.0
 icon: https://gitlab.com/gitlab-com/gitlab-artwork/raw/master/logo/logo-square.png