Update .gitlab-ci.yml

.gitlab-ci.yml

@@ -8,6 +8,14 @@ build:xenial:
     image: ubuntu:xenial
     <<: *install_definition
 
-build:latest:
-    image: ubuntu:latest
+build:bionic:
+    image: ubuntu:bionic
+    <<: *install_definition
+
+build:cosmic:
+    image: ubuntu:cosmic
+    <<: *install_definition
+    
+build:disco:
+    image: ubuntu:disco
     <<: *install_definition
\ No newline at end of file