Fix base64 decode

[sacOO7]

• JWT issued by laravel-broadcaster is base64UrlEncoded ->

  laravel-broadcaster/src/Utils.php

  Line 26 in 7c2eedb

  public static function generateJwt($headers, $payload, $key)

  .
• But while decoding, we use normal base64_decode method, this needs to be updated ->

  laravel-broadcaster/src/Utils.php

  Line 12 in 7c2eedb

  public static function parseJwt($jwt)

  .
• This needs to be updated on both client (laravel-echo) and server(laravel-broadcaster) side.

┆Issue is synchronized with this Jira Task by Unito