Bump ext-mongodb dependency to 0.6.0

Author: jmikola

composer.json

@@ -10,7 +10,7 @@
         { "name": "Derick Rethans", "email": "[email protected]" }
     ],
     "require": {
-        "ext-mongodb": ">=0.5.1"
+        "ext-mongodb": ">=0.6.0"
     },
     "autoload": {
         "psr-4": { "MongoDB\\": "src/" }