Update vendor dependencies

Change-Id: I3b1ca9f2687388c831d9d46a4e1de413ffae06ac

vendor/github.com/karrick/godirwalk/readdir.go

@@ -0,0 +1,47 @@
+package godirwalk
+
+// ReadDirents returns a sortable slice of pointers to Dirent structures, each
+// representing the file system name and mode type for one of the immediate
+// descendant of the specified directory. If the specified directory is a
+// symbolic link, it will be resolved.
+//
+// If an optional scratch buffer is provided that is at least one page of
+// memory, it will be used when reading directory entries from the file system.
+//
+//    children, err := godirwalk.ReadDirents(osDirname, nil)
+//    if err != nil {
+//        return nil, errors.Wrap(err, "cannot get list of directory children")
+//    }
+//    sort.Sort(children)
+//    for _, child := range children {
+//        fmt.Printf("%s %s\n", child.ModeType, child.Name)
+//    }
+func ReadDirents(osDirname string, scratchBuffer []byte) (Dirents, error) {
+	return readdirents(osDirname, scratchBuffer)
+}
+
+// ReadDirnames returns a slice of strings, representing the immediate
+// descendants of the specified directory. If the specified directory is a
+// symbolic link, it will be resolved.
+//
+// If an optional scratch buffer is provided that is at least one page of
+// memory, it will be used when reading directory entries from the file system.
+//
+// Note that this function, depending on operating system, may or may not invoke
+// the ReadDirents function, in order to prepare the list of immediate
+// descendants. Therefore, if your program needs both the names and the file
+// system mode types of descendants, it will always be faster to invoke
+// ReadDirents directly, rather than calling this function, then looping over
+// the results and calling os.Stat for each child.
+//
+//    children, err := godirwalk.ReadDirnames(osDirname, nil)
+//    if err != nil {
+//        return nil, errors.Wrap(err, "cannot get list of directory children")
+//    }
+//    sort.Strings(children)
+//    for _, child := range children {
+//        fmt.Printf("%s\n", child)
+//    }
+func ReadDirnames(osDirname string, scratchBuffer []byte) ([]string, error) {
+	return readdirnames(osDirname, scratchBuffer)
+}