Protect branches from deleting

Hi @sanemat,

I don't know if this feature is off the concept of this extension. I and my team sometimes accidently delete production branch after the branch is merged to master. I know a restore button appears after you remove a branch, but it's not good to delete important branches even in 3 seconds.
So, is it possible to merge this feature? If not, that's totally fine. I should make another extension!


Thanks.
https://github.com/sanemat/do-not-merge-wip-for-github/blob/87ebbb6c4a8a798f55bc3505eec0e4fbac278414/Gruntfile.js#L182-L184

のところでcssは`/styles/main.css`にまとめられるようなので、ここは`styles/main.css`でしょうか