CI: Add docs deployment job (MR 2316)

Tweaked-By: Oliver Smith <ollieparanoid@postmarketos.org>

.gitlab-ci.yml

@@ -17,6 +17,7 @@ before_script: &global_before_scripts
 
 stages:
   - lint
+  - deploy
   - test
 
 codespell:
@@ -72,3 +73,18 @@ docs:
   artifacts:
     paths:
       - public
+
+deploy:
+  only:
+    - master
+  stage: deploy
+  before_script:
+    - apk -q add openssh-client rsync
+  script:
+    - mkdir "${HOME}/.ssh"
+    - echo "${SSH_HOST_KEY}" > "${HOME}/.ssh/known_hosts"
+    - echo "${SSH_PRIVATE_KEY}" > "${HOME}/.ssh/id_ed25519"
+    - chmod 700 "${HOME}/.ssh/id_ed25519"
+    - rsync -hrvz --delete -e "ssh -p ${SSH_PORT}" public/ "${SSH_HOST}":/var/www/docs.postmarketos.org/pmbootstrap/
+  environment:
+    name: deploy