Remove syncjob from CI

.gitlab-ci.yml

 variables:
   BUILD_DIR: dist
-  MIRROR_REPO: git@github.com:thm-projects/arsnova-lite.git
-
 
 stages:
   - codestyle
@@ -95,18 +93,3 @@ deploy:
     - ssh-keyscan "$SERVER_URL" >> ~/.ssh/known_hosts
     - ssh-add <(echo "$SSH_PRIVATE_KEY")
     - scp -r "$BUILD_DIR"* "$SSH_URL"
-
-sync_mirror:
-  stage: deploy
-  tags:
-    - git
-  when: always
-  allow_failure: true
-  dependencies: []
-  script:
-    - eval $(ssh-agent -s)
-    - mkdir ~/.ssh && echo "$SYNC_SSH_KNOWN_HOSTS" > ~/.ssh/known_hosts
-    - ssh-add <(echo "$SYNC_SSH_PRIVATE_KEY")
-    - git clone --bare "$CI_REPOSITORY_URL" mirror.git
-    - cd mirror.git
-    - git push --mirror "$MIRROR_REPO"