Fatal error: Uncaught Error: Class 'Composer\Installer\LibraryInstaller' not found in C:\web\hncamp_admin_bak0623\vendor\topthink\think-installer\src\LibraryInstaller.php:9 Stack trace: #0 {main} thrown in C:\web\hncamp_admin_bak0623\vendor\topthink\think-installer\src\LibraryInstaller.php on line 9