install bash

.gitlab-ci.yml

 # This file is a template, and might need editing before it works on your project.
 # Full project: https://gitlab.com/pages/plain-html
-image: bash
+image: alpine
 pages:
   stage: deploy
   script:
-    - echo "The site will be deployed to $CI_PAGES_URL"
+    - apk add bash
     - ./scripts/generate-keys.sh
   artifacts:
     paths: