fix php version constraint

Author: dbu

composer.json

@@ -27,7 +27,7 @@
         }
     ],
     "require": {
-        "php": "^5.6|7.0.x",
+        "php": "^5.6|^7.0",
         "phpcr/phpcr-implementation": "2.1.*",
         "phpunit/phpunit": "^5.7"
     },