specify docker image

.gitlab-ci.yml

@@ -35,7 +35,7 @@ testwindows:
   # This is the default image
   #image: gitlab/gitlab-runner-helper:x86_64-7f7a4bb0-servercore1809
   # This image would work, but there is no powershell found
-  #image: mcr.microsoft.com/windows/nanoserver:1809-amd64
+  image: mcr.microsoft.com/windows/nanoserver:1809-amd64
   script:
     - echo "HELLO WINDOWS from the  $CI_COMMIT_BRANCH branch "
     - echo "(by $GITLAB_USER_LOGIN)"