Fix gitlab ci file

Integrate service in stage.

.gitlab-ci.yml

-services:
-  - swissbib/sftp-test-env:latest
-
 variables:
   DOCKER_TLS_CERTDIR: ""
 
@@ -11,6 +8,8 @@ stages:
 test:
   stage: test
   image: openjdk:8
+  services:
+    - swissbib/sftp-test-env:latest
   script:
     - ./gradlew --no-daemon test --fail-fast --tests "org.memobase.Tests"