fix: check packageFiles before length

lib/workers/repository/extract/index.js

@@ -13,7 +13,7 @@ async function extractAllDependencies(config) {
     const managerConfig = getManagerConfig(config, manager);
     managerConfig.manager = manager;
     const packageFiles = await getManagerPackageFiles(config, managerConfig);
-    if (packageFiles.length) {
+    if (packageFiles && packageFiles.length) {
       fileCount += packageFiles.length;
       logger.info(`Found ${manager} package files`);
       extractions[manager] = packageFiles;