fix repo key updates on each puppet run

[hensema]

This PR fixes the repo key updates on each puppet run in issue #20

It properly uses the notify/refreshonly parameters on the resources. Now the key is only updated when the repository file is updated.

[Yggdrasil]

Thanks for this PR. I ran into the same issue and your fix seems correct.

There are some formatting problems with the PR because you're using leading tabs instead of the spaces the existing code uses. I would suggest changing that, then you have my vote for getting it merged.

[hensema]

Please don't reject patches on formatting issues, it's offensive to your contributers (me). I don't know the requirements on each and every project.

I suggest embracing your contributors and reformatting the patch after accepting it. And leave them a note requesting proper formatting as per project requirements the next time.

[Yggdrasil]

@hensema Sorry, I'm not the maintainer. I probably should've made clearer that I'm just another contributer with some feedback in the hopes of getting this problem fixed. In my experience the better a pull request the more quickly it is merged since OSS maintainers are frequently busy people. Hence my suggestion, which is not a requirement or rejection at all. Again, thanks for your effort.