N°5809 Fix compilation error due to CASLogger VS LoggerInterface in psr/log

"Declaration of Combodo\iTop\Cas\CASLogger::emergency($message, array $context = []) must be compatible with Psr\Log\LoggerInterface::emergency(Stringable|string $message, array $context = [])"

psr/log 3.0.0 brings the BC break
Switching to 2.0.0 is nice as it will bring improvements for PHP 8.0+ !
So adding psr/log ^2.0.0 to composer.json

lib/psr/log/src/NullLogger.php

@@ -23,7 +23,7 @@ class NullLogger extends AbstractLogger
      *
      * @throws \Psr\Log\InvalidArgumentException
      */
-    public function log($level, string|\Stringable $message, array $context = []): void
+    public function log($level, string|\Stringable $message, array $context = [])
     {
         // noop
     }