Fix Deprecation error caused by Pdsinterop\Solid\Auth\Exception\Exception::jsonSerialize() not having a return type.

Author: Potherca

src/Exceptions.inc.php

@@ -4,7 +4,7 @@
 
 abstract class Exception extends \Exception implements \JsonSerializable
 {
-    final public function jsonSerialize()
+    final public function jsonSerialize(): array
     {
         return [
             'code' => $this->getCode(),
@@ -18,5 +18,4 @@ final public function jsonSerialize()
     }
 }
 
-
 class LogicException extends Exception {}