Update .gitlab-ci.yml file

.gitlab-ci.yml

@@ -3,6 +3,11 @@ 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
+
+  variables:
+    TWINE_USERNAME: $USER_NAME
+    TWINE_PASSWORD: $API_KEY
+
   image: python:slim
   script:
     - echo "Compiling the code..."