Fix path to maps in AdobeFontMetrics.php

`dirname(__FILE__)` gives you `php-font-lib/src/Fontlib`
`dirname(__FILE__) . '/../'` gives you `php-font-lib/src/`

We need one more level up, to hit /maps.

P.S.  We can also use `__DIR__ . '/../../'` OR `dirname(__DIR__) . '/../'`

src/FontLib/AdobeFontMetrics.php

@@ -33,7 +33,7 @@ function write($file, $encoding = null) {
 
     if ($encoding) {
       $encoding = preg_replace("/[^a-z0-9-_]/", "", $encoding);
-      $map_file = dirname(__FILE__) . "/../maps/$encoding.map";
+      $map_file = dirname(__FILE__) . "/../../maps/$encoding.map";
       if (!file_exists($map_file)) {
         throw new \Exception("Unknown encoding ($encoding)");
       }