Use Packagist V2 Metadata API

Author: swissspidy

src/Package_Command.php

@@ -834,7 +834,7 @@ private function get_package_by_shortened_identifier( $package_name, $insecure =
 		$options = [ 'insecure' => $insecure ];
 
 		// Check if the package exists on Packagist.
-		$url      = "https://repo.packagist.org/p/{$package_name}.json";
+		$url      = "https://repo.packagist.org/p2/{$package_name}.json";
 		$response = Utils\http_request( 'GET', $url, null, [], $options );
 		if ( 20 === (int) substr( $response->status_code, 0, 2 ) ) {
 			return $package_name;