Remove custom stuff for 7.2

.travis.yml

@@ -41,14 +41,12 @@ before_install:
     # see: https://blog.travis-ci.com/upcoming_ubuntu_11_10_migration/
     - if [[ $TRAVIS_PHP_VERSION = 5.3.3 ]]; then composer config -g -- disable-tls true; fi;
     - if [[ $TRAVIS_PHP_VERSION = 5.3.3 ]]; then composer config -g -- secure-http false; fi;
-    # no version compatible with PHP > 7.1
-    - if [[ $TRAVIS_PHP_VERSION = 7.2.* ]]; then composer remove friendsofphp/php-cs-fixer; fi;
 
 install:
     - composer self-update
 
 before_script:
-    - composer install --prefer-dist --no-interaction
+    - composer install -o --prefer-dist --no-interaction
 
 script:
     - mkdir -p build/logs