Drop hardcoded composer.json version key

This was causing packagist to not sync, therefore it needs to go.

Author: Ocramius

composer.json

@@ -2,7 +2,6 @@
     "name": "phptal/phptal",
     "homepage": "http://phptal.org/",
     "description": "PHPTAL is a templating engine for PHP5 that implements Zope Page Templates syntax",
-    "version":"1.3.1",
     "license": "LGPL-2.1+",
     "type": "library",
     "keywords": [