Add lowest setup.

Signed-off-by: Mior Muhammad Zaki <[email protected]>

Author: crynobone

.travis.yml

@@ -21,6 +21,7 @@ before_install:
 before_script:
   - if [[ $setup = 'basic' ]]; then travis_retry composer install --prefer-dist --no-interaction --no-suggest; fi
   - if [[ $setup = 'stable' ]]; then travis_retry composer update --prefer-dist --no-interaction --no-suggest --prefer-stable; fi
+  - if [[ $setup = 'lowest' ]]; then travis_retry composer update --prefer-dist --no-interaction --no-suggest --prefer-lowest --prefer-stable; fi
   - if [[ $setup = 'coveralls' ]]; then travis_retry composer require "php-coveralls/php-coveralls=^2.1" --prefer-dist --no-interaction --no-suggest --dev; fi
 
 script: