install script set to release 67 but should be v64

notice that the install script is trying to get release v67 but looking at the releases page the asset is **v64**

```
node-pre-gyp ERR! node -v v11.9.0
node-pre-gyp ERR! node-pre-gyp -v v0.6.39
node-pre-gyp ERR! not ok 
404 status code downloading tarball https://github.com/Microsoft/napajs/releases/download/0.4.0-pre/napa-v0.4.0-pre-node-v67-linux-x64.tar.gz
```