PHP 8.2 deprecation: `Using ${var} in strings is deprecated, use {$var} instead`

[ohader]

PHP 8.2 deprecation: Using ${var} in strings is deprecated, use {$var} instead in firebase/php-jwt/src/JWT.php:139

https://github.com/firebase/php-jwt/blob/main/src/JWT.php#L139

[Krisell]

There's an open PR resolving this: #446

[lolli42]

This one is fixed with the merge of #446 and can be closed.