fix: return shrinkwrapdir to avoid crash (#1621)

lib/workers/branch/lock-files.js

@@ -106,7 +106,12 @@ function determineLockFileDirs(config) {
           shrinkwrapYamlDirs.push(dirname);
         }
       }
-      return { packageLockFileDirs, yarnLockFileDirs, shrinkwrapYamlDirs };
+      return {
+        packageLockFileDirs,
+        npmShrinkwrapDirs,
+        yarnLockFileDirs,
+        shrinkwrapYamlDirs,
+      };
     }
   }
 

test/workers/branch/__snapshots__/lock-files.spec.js.snap

@@ -2,6 +2,9 @@
 
 exports[`workers/branch/lock-files determineLockFileDirs returns all directories if lock file maintenance 1`] = `
 Object {
+  "npmShrinkwrapDirs": Array [
+    "leftend",
+  ],
   "packageLockFileDirs": Array [
     "backend",
   ],