fix: removed extra comma in example "Validation.json" in README.md (#50)

Co-authored-by: Rahul Dodda <rahul.dodda@infor.com>
Co-authored-by: Natalia Maximo <t-nmaximo@microsoft.com>

README.md

@@ -34,7 +34,7 @@ Check out the [features](docs/features.md) docs for an overview of all quilla ca
           "action": "Validate",
           "type": "URL",
           "state": "Contains",
-          "target": "bing",
+          "target": "bing"
         }
       ]
     }