Upgrade PHPStan to 1.12.12

PHPStan was upgraded to 2.0 in November, but we're not ready
to upgrade as it detects a lot of new errors.
That said our first step is to upgrade to the latest 1.x.x
release, per:
https://github.com/phpstan/phpstan/blob/2.0.x/UPGRADING.md

There is one upside to this upgrade, which is to be able to
disable errors using their identifier (added in 1.11).

Also it seems like a low-value error was removed from L5,
so removed it from our configuration file.

Author: jchaffraix

composer.json

@@ -17,7 +17,7 @@
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^3.57",
         "phpunit/phpunit": "^9.6",
-        "phpstan/phpstan": "^1.10"
+        "phpstan/phpstan": "^1.12"
     },
     "replace": {
         "symfony/polyfill-ctype": "*",

composer.lock

@@ -35,7 +35,6 @@ parameters:
         - message: '#Constant .* not found#'
 
         # Low value and frequent L5 errors that are ignored by default.
-        - message: "#^Parameter \\#1 \\$.* of function array_multisort is passed by reference, so it expects variables only\\.$#"
         - message: '#^Parameter \#\d+ .* of (static )?(function|method) .* expects string(\|null)?, int.* given\.$#'
 
         # TODO(jchaffraix): Temporarily disabling those as they are dynamically created (see comment in Pool's constructor).