Update ReadDir to return []os.DirEntry

[lordofscripts]

Background

In old projects you usually hear "because of history", well, blang/vfs nor its clones are an exception. The original project came to light 9+ years ago, but already in 2021 the ReadDir() operation with an uppercase "D" in Dir came to GO v1.16.

The Problem

VFS and all its clones date earlier than that and they all suffer from the Filesystem.ReadDir() interface function to be non-compliant with the current standard. In VFS Filesystem.ReadDir() returns []os.FileInfo whereas the real os.ReadDir() function returns []os.DirEntry instead.