Fix syscall.Dup2 missing on some systems

What's Changed

• Use unix library for Dup2 support by @rgalanakis in #2

Full Changelog: v0.1.0...v0.1.1

Initial tagged release

Everything in upstream plus the CaptureCGo race condition crash/fix in #1

What's Changed

• Fix race conditions in Capture/CaptureWithCGo by @rgalanakis in #1

Full Changelog: https://github.com/lithictech/osutil/commits/v0.1.0