Update zend-soap #37

Update zend-soap to the version that supports PHP 7.2 - ver. 2.7.0
composer.lock already has zend-soap in version 2.7.0, this information
was missing in composer.json.

Author: cieslix

composer.json

@@ -78,7 +78,7 @@
         "zendframework/zend-server": "^2.6.1",
         "zendframework/zend-servicemanager": "^2.7.8",
         "zendframework/zend-session": "^2.7.3",
-        "zendframework/zend-soap": "^2.6.0",
+        "zendframework/zend-soap": "^2.7.0",
         "zendframework/zend-stdlib": "^2.7.7",
         "zendframework/zend-text": "^2.6.0",
         "zendframework/zend-uri": "^2.5.1",