switch to hugomods hugo image

As the current image is out-of-date, the GitLab documentation also uses
a hugomods image and as we're already using one in other repos, switch
to it.

Match the hugo version currently in use for now as the latest version
doesn't build the website.

https://docs.gitlab.com/tutorials/hugo/#add-your-gitlab-configuration-options
https://docker.hugomods.com/
https://github.com/hugomods/docker
https://hub.docker.com/r/hugomods/hugo

.forgejo/workflows/deploy.yaml

@@ -13,7 +13,7 @@ jobs:
   build:
     runs-on: docker
     container:
-      image: registry.gitlab.com/pages/hugo/hugo_extended:latest
+      image: hugomods/hugo:debian-node-lts-0.140.2
     steps:
       - name: Pipeline info
         run: |