[laravel/laravel] Release v7.3.0 - v7.3.0

DRANK

### Added - Add serialize option to array cache config ([#5244](https://github.com/laravel/laravel/pull/5244)) - Add Mailgun and Postmark mailer ([#5243](https://github.com/laravel/laravel/pull/5243)) - Add new SQS queue suffix option ([#5252](https://github.com/laravel/laravel/pull/5252)) - Allow configuring the timeout for the smtp driver ([#5262](https://github.com/laravel/laravel/pull/5262)) ### Changed - Cleanup session config ([#5261](https://github.com/laravel/laravel/pull/5261)) ### Fixed - Ensure that `app.debug` is a bool ([5ddbfb8](https://github.com/laravel/laravel/commit/5ddbfb845439fcd5a46c23530b8774421a931760)) - Fix S3 endpoint url reference ([#5267](https://github.com/laravel/laravel/pull/5267)) - Update default CORS config ([#5259](https://github.com/laravel/laravel/pull/5259)) ### Removed - Remove `view.expires` config entry ([641fcfb](https://github.com/laravel/laravel/commit/641fcfb60aa47266c5b4767830dc45bad00c561c))