add manual job to push Helm chart to Gitea OCI registry

.gitlab-ci.yml

@@ -11,6 +11,8 @@ variables:
   CHART_VERSION: "1.0.8"
   PACKAGE_PATH: "packages"
   HELM_EXPERIMENTAL_OCI: "1"
+  GITEA_URL: "gitea.infrastructure.helmholz.cloud"
+  GITEA_REPO: "oci://gitea.infrastructure.helmholz.cloud/gitea_admin/helm"
 
 package_chart:
   stage: package
@@ -38,3 +40,21 @@ publish_chart:
            "${CI_API_V4_URL}/projects/${CI_PROJECT_ID}/packages/helm/api/stable/charts"
   only:
     - main
+
+push_chart_to_gitea:
+  stage: publish
+  image:
+    name: alpine/helm:3.14.0
+    entrypoint: [""]
+  variables:
+    GITEA_URL: "https://gitea.infrastructure.helmholz.cloud"
+    GITEA_USERNAME: "gitea_admin"
+    GITEA_PASSWORD: "$GITEA_PASSWORD"
+  script:
+    - echo "$GITEA_PASSWORD" | helm registry login $GITEA_URL --username $GITEA_USERNAME --password-stdin
+    - helm push ${PACKAGE_PATH}/${CHART_NAME}-${CHART_VERSION}.tgz $GITEA_REPO
+  when: manual
+  only:
+    - main
+  dependencies:
+    - package_chart