scope the "image" only to the build job, and specify a SITE_URL

The SITE_URL was moved from the project's CI/CD variables back into
the YAML file, because they were "scoped" there and the template now
expects them to be "unscoped".

The image should be scoped to the build job only otherwise the
imported jobs from the template will fail because they will not have
the right image configured.

.gitlab-ci.yml

@@ -3,23 +3,21 @@
 #
 # This file is very similar to the existing GitLab template, and might need editing before it works on your project.
 #
-# All available Hugo versions are listed here:
-# https://gitlab.com/pages/hugo/container_registry
-#
-# cState uses Hugo Extended.
-image: registry.gitlab.com/pages/hugo/hugo_extended:0.65.3
-
 variables:
   GIT_SUBMODULE_STRATEGY: recursive
   SUBDIR: public/
-  # now from environment
-  #SITE_URL: status.torproject.org
+  SITE_URL: status.torproject.org
 
 include:
   project: tpo/tpa/ci-templates
   file: static-shim-deploy.yml
 
+# All available Hugo versions are listed here:
+# https://gitlab.com/pages/hugo/container_registry
+#
+# cState uses Hugo Extended.
 build:
+  image: registry.gitlab.com/pages/hugo/hugo_extended:0.65.3
   stage: build
   script:
     - hugo