CI: check the lv6 manual build

.gitlab-ci.yml

@@ -7,6 +7,17 @@ stages:
   - build
   - test
   - release
+
+
+lv6-man:
+  image: jahierwan/verimag-sync-papers
+  allow_failure: true
+  script:
+    - cd lv6-ref-man
+    - make doc
+  artifacts:
+    paths:
+      - doc
   
 build:
   stage: build