Fix CI config

.gitlab-ci.yml

@@ -33,6 +33,6 @@ build_image:
   script:
     - docker build -t clarinpl/speller2 .
     - echo $DOCKER_PASSWORD > pass.txt
-    - cat pass.txt | docker login --username $DOCKER_USERNAME --password-stdin
+    - cat pass.txt | docker login -u $DOCKER_USERNAME -p-stdin
     - rm pass.txt
     - docker push clarinpl/speller2