Update .gitlab-ci.yml, change master deploymnet branch

.gitlab-ci.yml

 production:
   script:
-  - rsync -a ./mymodule/ /var/simplesamlphp/modules/mymodule/
+  - rsync -a ./mymodule/ /data/simplesamlphp/modules/mymodule/
   only: 
   - master
   tags: