add initial ci job

.gitlab-ci.yml

@@ -0,0 +1,28 @@
+build:
+  stage: build
+  image:
+    name: antora/antora:latest
+  script:
+  - antora --log-failure-level fatal site.yml
+  artifacts:
+    paths:
+    - public/
+    expire_in: 1 week
+    expose_as: 'docs preview'
+  rules:
+  - if: $CI_PIPELINE_SOURCE == 'merge_request_event'
+  environment:
+    name: preview MR_${CI_MERGE_REQUEST_IID}
+    url: https://${CI_SERVER_HOST}/${CI_PROJECT_PATH}/-/jobs/${CI_JOB_ID}/artifacts/file/public/index.html
+pages:
+  stage: build
+  image:
+    name: antora/antora:latest
+  script:
+  - antora site.yml
+  artifacts:
+    paths:
+    - public
+  rules:
+  - if: $CI_COMMIT_BRANCH == "main"
+