remove sign-off-check from drone because we have DCO bot for it

Signed-off-by: Jonas Sulzer <jonas@violoncello.ch>

.drone.yml

@@ -24,23 +24,6 @@ pipeline:
       matrix:
         TESTS: check-app-compatbility
 
-  signed-off-check:
-    image: nextcloudci/php7.2:php7.2-9
-    environment:
-      - APP_NAME=user_external
-      - CORE_BRANCH=master
-      - DB=sqlite
-    commands:
-      - wget https://raw.githubusercontent.com/nextcloud/travis_ci/master/before_install.sh
-      - bash ./before_install.sh $APP_NAME $CORE_BRANCH $DB
-      - cd ../server
-      - php ./build/signed-off-checker.php
-    secrets: [ github_token ]
-    when:
-      matrix:
-        TESTS: signed-off-check
-
 matrix:
   include:
-    - TESTS: signed-off-check
     # - TESTS: check-app-compatbility