use job token instead of project var

.gitlab-ci.yml

 image: docker:stable
-
 services:
   - docker:dind
   
 variables:
   DOCKER_HOST: tcp://docker:2376
   DOCKER_TLS_CERTDIR: "/certs"
+  DOCKER_BUILDKIT: 1
     
 build docker-planemo:
   stage: build
-  
+  image: docker:stable
+  services:
+    - docker:dind
   variables:
     IMAGE_TAG: $CI_REGISTRY/record/docker-planemo/singularity-planemo-galaxy:0.74.9
-    DOCKER_BUILDKIT: 1
-  
-  script:
+  before_script:
     - docker info
-    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - echo $CI_JOB_TOKEN | docker login -u $CI_REGISTRY_USER --password-stdin $CI_REGISTRY  
+  script:
     - docker build --build-arg BUILDKIT_INLINE_CACHE=1 -t $IMAGE_TAG .
+  after_script:
     - docker push $IMAGE_TAG