PHP 7.4 code is not (fully) supported

[LukeWCS]

Hello

I have started using features from PHP 7.4 in one of my extensions. Up until now, the code base of my extensions was consistently 7.1. I noticed that EPV does not recognize at least two 7.4 features and generates false reports. This affects typed class properties and the Null Coalescing Assignment Operator.

Tested with EPV 0.0.12 and PHP 7.4.33.

1. Typed properties:

The following block:

	protected object $common;
	protected object $ext_manager;
	protected object $cache;
	protected object $request;
	protected object $log;
	protected object $user;
	protected object $config;
	protected object $config_text;
	protected object $language;
	protected object $template;
	protected object $db;
	protected string $table_prefix;
	protected string $phpbb_root_path;
	protected string $php_ext;

	protected string $u_action;
	protected array  $migrations_db;
	protected int    $safe_time_limit;
	protected bool   $is_phpbb_min_3_3_8;

produces the following false message:

Fatal error: PHP parse error in file \core\ext_mgr_plus.php. Message: Syntax error, unexpected T_STRING, expecting T_FUNCTION or T_CONST on line 42

2. NCAO

The following line:

		$ext_list_vc ??= [];

produces the following false message:

Fatal error: PHP parse error in file \core\ext_mgr_plus.php. Message: Syntax error, unexpected on line 924

Both errors also cause EPV to terminate immediately and thus the rest of the file is no longer checked.