Apply some standard Ruby style conventions

[dgoodlad]

Let me preface this: I normally hate whitespace commits/pull requests. However, there are some broadly accepted Ruby style conventions that I think are valuable to follow, if only to make it easier for other Ruby devs to contribute. Please feel free to disregard this PR if you don't agree :wink:

Doing a git diff --ignore-space-change lists only a few actual lines of diff, from revs c4e31fe and e8146db. The main whitespace change is 2-space soft tab indentation, which hides those two real changes since every line has been touched.

[glennpratt]

:+1:

PS Github has a nice trick: w=1

https://github.com/crayfishx/hiera-gpg/pull/19/files?w=1

[dgoodlad]

@glennpratt right, nice call, thanks for linking straight to it too!

Now hopefully @crayfishx agrees with these changes :smirk:

[dLobatog]

I was about to do the same, +1 to this. @crayfishx ?