Update: use a named version folder in NPM tarballs (#4094)
**Summary**
Fixes #3758. Makes the top-level folder in the tar archives have a name like `yarn-vX.Y.Z` instead of `dist` using the `--transform` and `-s` options in `tar` (they are different in GNU and BSD `tar`).
**Test plan**
Run `yarn build-dist` and then `tar -ztvf artifacts/yarn-v1.0.0.tar.gz`. Make sure the output lists all the files under `yarn-v1.0.0` directory.
