Update .gitlab-ci.yml to test with Odin (ubuntu:blaar)

use apt-get to avid warnings

.gitlab-ci.yml

 .install_script: &install_definition
     script:
-        - apt update
-        - apt install -y wget sudo
+        - apt-get update
+        - apt-get install -y wget sudo
         - wget -O - https://git.u-cergy.fr/blaar/blaar/raw/master/developer_tools/clone_and_install_blaar_ubuntu.sh | bash
 
 build:xenial:
@@ -19,4 +19,8 @@ build:cosmic:
 # Ignore disco for now.
 #build:disco:
 #    image: ubuntu:disco
-#    <<: *install_definition
\ No newline at end of file
+#    <<: *install_definition
+
+build:
+    image: ubuntu:blaar
+    <<: *install_definition
\ No newline at end of file