fixed error "Undefined array key" when trying to validate a nullable route parameter

Author: DeveloperMarius

src/Pecee/Http/Input/InputValidator.php

@@ -252,7 +252,7 @@ public static function parseValidatorFromRouteParameters(Router $router, IRoute
                                     $routeAttribute->addValidator('nullable');
                             }
                             $settings[$routeAttribute->getName()] = $routeAttribute->getFullValidator();
-                            $parsedData[$routeAttribute->getName()] = (new InputParser(new InputItem($routeAttribute->getName(), $parsedData[$routeAttribute->getName()])))->parseFromSetting($routeAttribute->getType())->getValue();
+                            $parsedData[$routeAttribute->getName()] = (new InputParser(new InputItem($routeAttribute->getName(), $parsedData[$routeAttribute->getName()] ?? null)))->parseFromSetting($routeAttribute->getType())->getValue();
                         }
                     }
                     $routeAttributeValidator = InputValidator::make()->setRules($settings);