Check crash on `$parser->getUrl()`

[bfabio]

getUrl() raises a TypeError:

Fatal error: Uncaught TypeError: Bfabio\PublicCodeParser\PublicCode::getUrl(): Return value must be of type string, array returned in /app/vendor/bfabio/publiccode-parser-php/src/PublicCode.php:25
Stack trace:
#0 /app/test.php(46): Bfabio\PublicCodeParser\PublicCode->getUrl()
#1 {main}
  thrown in /app/vendor/bfabio/publiccode-parser-php/src/PublicCode.php on line 25