Update .gitlab-ci.yml file

.gitlab-ci.yml

@@ -7,7 +7,7 @@ stages:          # List of stages for jobs, and their order of execution
 build-job:       # This job runs in the build stage, which runs first.
   stage: build
   script:
-    - ant build
+    - javac build.xml
   artifacts:
     paths:
       - ./build.xml.*