Try removing composer.lock to make sure we get latest version of collabora

.travis.yml

@@ -46,6 +46,7 @@ before_script:
   - sudo service apache2 restart
   - php -m
   - php -i
+  - rm composer.lock
   - php install-cli.php --ignore-platform-reqs
   # create data directory
   - sudo mkdir /var/lib/egroupware