Update travis.

Signed-off-by: Mior Muhammad Zaki <crynobone@gmail.com>

.travis.yml

@@ -16,9 +16,11 @@ env:
     - setup=lowest
     - setup=stable
 
-before_script:
+before_install:
   - travis_retry composer self-update
   - composer config discard-changes true
+
+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