Fix PHP 7.2 issue with signature of __destruct()

Author: mlocati

src/Base/Archive/InfozipUnzipper.php

@@ -57,7 +57,7 @@ public function __construct(string $path)
      *
      * @see \Pickle\Base\Interfaces\Archive\Unzipper::__destruct()
      */
-    public function __destruct(): void
+    public function __destruct()
     {
     }
 

src/Base/Archive/PHPUnzipper.php

@@ -56,7 +56,7 @@ public function __construct(string $path)
      *
      * @see \Pickle\Base\Interfaces\Archive\Unzipper::__destruct()
      */
-    public function __destruct(): void
+    public function __destruct()
     {
         parent::__destruct();
     }

src/Base/Interfaces/Archive/Unzipper.php

@@ -50,7 +50,7 @@ public function __construct(string $path);
     /**
      * Close the archive.
      */
-    public function __destruct(): void;
+    public function __destruct();
 
     /**
      * Extract the archive contents to a specific directory.