Replace node-tar with system wide tar commands since only Cygwin

Got the following with gmp tarball

  bale:error TAR_BAD_ARCHIVE: Unrecognized archive format +0ms
  bale:error Error: TAR_BAD_ARCHIVE: Unrecognized archive format

Tarball: https://ftp.gnu.org/gnu/gmp/gmp-6.2.1.tar.xz#0578d48607ec0e272177d175fd1807c30b00fdf2

We anyways only need to support cygwin-like environment.

README.md

@@ -2,6 +2,8 @@
 
 A tool to make it easier to package C libraries and tools for [esy](esy.sh)
 
+Note: On Windows, it works only within mingw/cygwin environment since esy provides this environment anyway.
+
 ## Development
 
 (Currently Windows only) Set `NODE_ENV` to `development` to enable sourcemaps at the node wrapper. Not useful inside the JS realm.