Update .gitlab-ci.yml file

.gitlab-ci.yml

@@ -38,6 +38,7 @@ stages:
   -   git checkout devel
   -   git pull
   -   git checkout $WOLF_CORE_BRANCH
+  -   git pull
   - else
   -   git clone ssh://git@gitlab.iri.upc.edu:2202/mobile_robotics/wolf_projects/wolf_lib/wolf.git
   -   cd wolf