Make the enum element comparison strict

The current check is matching numeric strings that are not equal ( like "604.1" == "604.10" because of PHP's == behavior that converts numeric strings to numbers and then performs a numeric comparison), even if type is checked before the comparison, the value should be identic

src/JsonSchema/Constraints/Enum.php

@@ -28,11 +28,11 @@ class Enum extends Constraint
         }
 
         foreach ($schema->enum as $enum) {
-            if ((gettype($element) === gettype($enum)) && ($element == $enum)) {
+            if ((gettype($element) === gettype($enum)) && ($element === $enum)) {
                 return;
             }
         }
 
         $this->addError($path, "does not have a value in the enumeration " . print_r($schema->enum, true));
     }
-}
+}