Merge pull request #3 from andrewreshetnikov/change_php_version

Change php version in composer.json and .travis.yml

Author: ngorborukov

.travis.yml

@@ -1,9 +1,8 @@
 language: php
 
 php:
-  - 5.3
-  - 5.4
   - 5.5
+  - 5.6
 
 before_script:
     - composer install --dev

composer.json

@@ -15,7 +15,7 @@
     ],
 
     "require": {
-        "php": ">=5.3.3",
+        "php": "^5.5.9|>=7.0.8",
         "symfony/framework-bundle": "^3.3",
         "opensoft/simple-serializer": ">=1.0.0"
     },