Does not find package.json(s) when current working directory is a symbolic link.

[AdamVanScyoc]

Hi, thanks for dusti-lock, I've been playing with it and its a helpful tool.

I noticed that when I'm in a symlinked directory, dusti-lock doesn't find package.json files.

Steps to repro:

1. Clone this test repo I created: https://github.com/AdamVanScyoc/dusti_test
2. run dusti-lock in the base directory and observe that it finds package.json, and reports that it found an unregistered Node package
3. From repo root, cd dusti_test_link/
4. run dusti-lock and observe that it finishes instantly and does not report the unregistered package as before.

┌─[Adam@89]─[~/repos/dusti-lock]
└──╼ $go version
go version go1.14.3 darwin/amd64
┌─[Adam@89]─[~/repos/dusti-lock]
└──╼ $git version
git version 2.28.0
┌─[Adam@89]─[~/repos/dusti-lock]
└──╼ $sh --version
GNU bash, version 3.2.57(1)-release (x86_64-apple-darwin19)
Copyright (C) 2007 Free Software Foundation, Inc.

I can provide any relevant version numbers or env. details you need. Thanks again