Scoop: Add `scoop version` to report the git tag (when implemented)

[Ghasan]

Thank you for this awesome tool, it is really handy and minimal.

However, I realized there is no way to get scoop version.

Normally for CLI tools, we just "command --version" to get its details, but there is nothing like this when I checked the help.

[r15ch13]

Scoop uses Git to update itself and doesn't use versions. You could say it's a rolling release.
--version could print the current git commit it's based on.

[styfle]

@r15ch13 Git has the concept of tags which could be used to label each release.
Consequently, tags will show up under GitHub releases.

[r15ch13]

@styfle Agreed, but that's a decision for @lukesampson to make 😄

[lukesampson]

So is the idea to tag as "releases" the commits that affect the program code, rather than just affecting the manifests? I'd be fine with that.

[rasa]

Would it make sense to move the main bucket to its own branch, or even a separate repo?