Use ~ versioning instead of ^

Author: tomphp

.travis.yml

@@ -1,5 +1,6 @@
 language: php
 before_script:
+  - composer self-update
   - composer install --dev --prefer-dist
 script: php vendor/bin/phpunit; php vendor/bin/behat --format progress
 php:

composer.json

@@ -11,18 +11,18 @@
         "nikic/php-parser": "@stable",
         "beberlei/assert": "@stable",
         "andrewsville/php-token-reflection": "@stable",
-        "symfony/finder": "^2.4.0@stable",
-        "symfony/console": "^2.4.0@stable",
-        "tomphp/patch-builder": "^0.1"
+        "symfony/finder": "~2.4@stable",
+        "symfony/console": "~2.4@stable",
+        "tomphp/patch-builder": "~0.1"
     },
 
     "require-dev": {
         "php": ">=5.4",
-        "behat/behat": "^2.5@stable",
+        "behat/behat": "~2.5@stable",
         "mikey179/vfsStream": "@stable",
         "phake/phake": "@stable",
         "symfony/process": "@stable",
-        "phpunit/phpunit": "^4.6@stable"
+        "phpunit/phpunit": "~4.6@stable"
     },
 
     "autoload": {