Changed composer setting for sample code while running travis

Author: ashtru

.travis.yml

@@ -15,7 +15,7 @@ before_script:
 script:
     - vendor/phpunit/phpunit/phpunit --coverage-clover=coverage.clover
     - cd sample-code-php
-    - composer install --prefer-dist --ignore-platform-reqs
+    - composer install --prefer-dist
     - vendor/phpunit/phpunit/phpunit test-runner.php .
 
 after_script: