Twig 3.9 deprecation

[shmshd]

Node implementations that use echo or print should use yield instead and use #[YieldReady] attribute. Given this requirement for Twig 3.9, PHP 8 should be the minimum supported version. Is there any reason to support PHP 7?

Currently, there are 3 warnings, 1 from NodeVisitor/YieldNotReadyNodeVisitor.php and 2 from the Compiler.php.

Deprecation message:

User Deprecated: Since twig/twig 3.9: Using "echo" is deprecated, use "yield" instead in "NotFloran\MjmlBundle\Twig\Node", then flag the class with #[YieldReady].

Changelog: https://github.com/twigphp/Twig/blob/ad934312cd08b6b466932fdfdd5b97ae680bc28a/CHANGELOG#L25-L29