Fix PrepareCommand::fixComposerJson()

Author: ondrejmirtes

compiler/src/Console/PrepareCommand.php

@@ -64,7 +64,7 @@ private function fixComposerJson(string $buildDir): void
 
 		unset($json['replace']);
 		$json['name'] = 'phpstan/phpstan';
-		$json['require']['php'] = '^7.2';
+		$json['require']['php'] = '^7.2|^8.0';
 
 		// simplify autoload (remove not packed build directory]
 		$json['autoload']['psr-4']['PHPStan\\'] = 'src/';