Whilst working on [this GTD issue](https://git.drupalcode.org/project/gitlab_templates_downstream/-/issues/3573349) I found that in the D7 pipeline neither of the variables `$DRUPAL_CORE` nor `$INSTALLED_DRUPAL_VERSION` are written to build.env. These are written in the modern version pipeline. This omission makes it harder to write some common config `before_script_actions` where nearly everything is the same and the version can be used to make it completely generic. See https://git.drupalcode.org/issue/gitlab_templates_downstream-3573349/-/jobs/9047593 I suggest that we write both of these variables to `build.env` for consistency and to help with that issue