Update .gitlab-ci.yml file

.gitlab-ci.yml

 
 .test_template: &test_definition
-  only:
-    - master
-
+  image: julia:1.10
+  stage: test
   script:
     - julia -e 'using Pkg; Pkg.clone(pwd()); Pkg.build("MultilevelChainSampler"); Pkg.test("MultilevelChainSampler"; coverage = true)'
     - julia -e 'using Pkg; Pkg.add("Coverage"); 
       import MultilevelChainSampler; cd(joinpath(dirname(pathof(MultilevelChainSampler)), ".."));
       using Coverage; cl, tl = get_summary(process_folder());
       println("(", cl/tl*100, "%) covered")'
-
-# Name a test and select an appropriate image.
-# images comes from Docker hub
-test:
-  image: julia:1.10
-  <<: *test_definition
-
+  only:
+  - master
 
 # Example documentation deployment
 pages: