Enable the official Gitlab - Sonarqube integration

See https://sonarqube.inria.fr/pages/documentation.html#3

.gitlab/sonarqube.yml

@@ -17,6 +17,8 @@ sonarqube:
   needs: [build]
   script:
     - ${CI_PROJECT_DIR}/tools/analysis.sh
+  variables:
+    GIT_DEPTH: "0"
   artifacts:
     name: "$CI_JOB_NAME-$CI_COMMIT_REF_SLUG"
     expire_in: 180 minutes