Update .gitlab-ci.yml, COPYRIGHT, README.md, main.json files

.gitlab-ci.yml

+image: alpine:latest
+
+pages:
+  stage: deploy
+  script:
+  - mkdir .public
+  - cp -r * .public
+  - mv .public public
+  artifacts:
+    paths:
+    - public
+  only:
+  - master

COPYRIGHT

+mp3/computer.mp3  by squashy555 (https://freesound.org/people/squashy555/sounds/273736/)
+mp3/spaceship.mp3 by BurghRecords (https://freesound.org/people/BurghRecords/sounds/415673/)
+mp3/timbregirlelevator.mp3 by Timbre (https://freesound.org/people/Timbre/sounds/528775/)

README.md

+# world-map-starterkit
+
+This repositor is intended to give you an overview over the features in the world as well as a good starting point for creating your own maps! Feel free to use and change them!
+