[ci] remove unneeded variable

.gitlab-ci.yml

@@ -80,7 +80,6 @@ prerelease:
     REPO_HOST: repo.data.kit.edu
     REPO_USER: cicd
     DOCKER_REGISTRY: https://index.docker.io/v1/
-    GODIR: /go/src/github.com/oidc-mytoken/server
   before_script:
     - echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin "$DOCKER_REGISTRY"
   script: