add images to helm_package commands

.gitlab/ci_templates/helm_package.yml

@@ -16,6 +16,9 @@ variables:
 
 .lint-helm:
   stage: lint-helm-chart
+  image:
+    name: alpine/helm:3.7.1
+    entrypoint: ["/bin/sh", "-c"]
   script:
     - cd ${CHART_DIR}
     - helm dep update
@@ -33,6 +36,9 @@ variables:
 
 .package-chart:
   stage: package-helm-chart
+  image:
+    name: alpine/helm:3.7.1
+    entrypoint: ["/bin/sh", "-c"]
   script:
     - cd ${CHART_DIR}
     - helm package .