Merge remote-tracking branch 'remotes/dev/release' to master

Author: rgrebenchuk

.travis.yml

@@ -11,6 +11,6 @@ env:
 before_script:
   - composer self-update
   - phpenv config-add travis.php.ini
-  - composer require symfony/symfony:${SYMFONY_VERSION} --prefer-source
+  - composer require symfony/symfony:${SYMFONY_VERSION} --prefer-dist
 
 script: phpunit --coverage-text