reignoring subdirectories of an unignored directory in .vscodeignore doesn't work...use the ignore npm package instead of your own logic

[jedwards1211]

Can we use the ignore npm package which conforms to the .gitignore spec instead of your own from-scratch logic? I'll make a PR.

Here's my .vscodeignore:

**
!node_modules
!out/
out/test
out/test/
out/test/*
out/test/**/*
!LICENSE.md
!package.json
!README.md
!yarn.lock

When I run vsce ls I still see files from out/test listed:

out/test/runTest.js
out/test/suite/extension.test.js
out/test/suite/index.js