Clean up & update example

Author: sebastiandedeyne

example/composer.json

@@ -1,6 +1,6 @@
 {
     "require": {
-        "spatie/phpunit-snapshot-assertions": "dev-master",
+        "spatie/phpunit-snapshot-assertions": "^1.0",
         "phpunit/phpunit": "^6.0"
     },
     "autoload": {

example/tests/OrderSerializerTest.php

@@ -21,7 +21,5 @@ public function it_can_serialize_an_order()
         ]);
 
         $this->assertMatchesJsonSnapshot($orderSerializer->serialize($order));
-        $this->assertMatchesJsonSnapshot($orderSerializer->serialize($order));
-        $this->assertMatchesJsonSnapshot($orderSerializer->serialize($order));
     }
 }