ENOENT while extracting an tar with hardlinks

File: `gcc-arm-none-eabi-9-2020-q2-update-mac.tar.bz2` from https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads/9-2020-q2-update

```
[Error: ENOENT: no such file or directory, link './arm-none-eabi/lib/libg.a' -> '/Users/XiNGRZ/****/arm-none-eabi/lib/libc.a'] {
errno: -2,
code: 'ENOENT',
syscall: 'link',
path: './arm-none-eabi/lib/libg.a',
dest: '/Users/XiNGRZ/****/arm-none-eabi/lib/libc.a'
}
```

Just did some investigation and found:

https://github.com/kevva/decompress/blob/84a8c1046946add1a6ae01c54dbebf312e4ffc85/index.js#L121

I think `x.linkname` should be joined with the `output` path. Otherwise `fsPromises.symlink` can't find the target.

Start in index.js at the linked line and reproduce the failure with gcc-arm-none-eabi-9-2020-q2-update-mac.tar.bz2. Trace how the hardlink target is resolved relative to the extraction output, then verify that extracting the archive creates the expected libc.a link without ENOENT.

Written by the indexing model from the issue text.