Add scoop installation to readme

[bonepl]

Hi, this should be quick.
I would add scoop (http://scoop.sh) installation instructions below Chocolatey in readme.

To install mvnd from scoop you need to
scoop install mvndaemon

It is available in main scoop repository, no additional setup required:
https://github.com/ScoopInstaller/Main/blob/master/bucket/mvndaemon.json

[gnodet]

Thx ! I'm currently trying to get a 0.8.0 out and a bunch of things will change regarding the way mvnd will be available (mainly from the ASF download mirrors), so I think the above json will have to change. I'd rather defer until this is fixed properly, but feel free to provide a PR so that we can merge it when 0.8.0 is out and the json fixed.

[bonepl]

I'm not a scoop repo maintainer, but its repository is kept up-to-date very well.

Here's the PR:
#647