Add Download Progress Bar

Hi, I would like to add a download progress bar while installation.

It's because current version will display `Your package has been installed!` even if the package is still downloading.
It will look like the installation is success but the `npm install` not finished.

For example:

```sh
blueworrybear@LAPTOP-0K8IJ0NA:~/projects/covergates-node$ npm install .

> covergates@0.1.6 postinstall /home/blueworrybear/projects/covergates-node
> node ./install.js

Downloading release https://github.com/covergates/covergates/releases/download/v0.1.6/covergates-v0.1.6-linux-amd64.tar.gz
covergates has been installed!
^C
blueworrybear@LAPTOP-0K8IJ0NA:~/projects/covergates-node$
```

I have make a code change, which could be referred here: [add download progress bar](https://github.com/blueworrybear/binary-install/commit/63a0bc8a2467fd581edf9b34690a5d2d9db235f8)
With the update, the stdout will look like:

```sh
blueworrybear@LAPTOP-0K8IJ0NA:~/projects/covergates-node$ npm install .

> covergates@0.1.6 postinstall /home/blueworrybear/projects/covergates-node
> node ./install.js

Downloading release from https://github.com/covergates/covergates/releases/download/v0.1.6/covergates-v0.1.6-linux-amd64.tar.gz
covergates in now installing
downloading [====================] 723152/bps 100% 0.0s

covergates has been installed!
npm WARN eslint-plugin-prettier@3.1.4 requires a peer of prettier@>=1.13.0 but none is installed. You must install peer dependencies yourself.

audited 138 packages in 45.738s

10 packages are looking for funding
run `npm fund` for details

found 0 vulnerabilities
```

---

I love this project, it's very useful! So please consider this idea. I will make a PR if you agree.

Beginne mit dem Lesen von install.js und überprüfe den referenzierten download-progress-Commit. Reproduziere die in der Issue gezeigte npm install-Ausgabe und überprüfe anschließend, dass der Download-Fortschritt angezeigt wird, während das Release abgerufen wird, und dass die Installationsmeldung erst nach Abschluss des Downloads erscheint.

Vom Indexierungsmodell aus dem Issue-Text verfasst.