Keep file permissions

[koehnlein]

First of all: Thanks for that great and useful plugin. I really like it!

I tried to move some of our project configuration files into a configuration package and everything worked fine, except of a git hook. The file is copied correctly to it's final place, but the "execute" file permission is not kept when the file is copied.

Did I miss a configuration? Here you can find my very simple manifest.json

{
  "files": {
    "pre-commit": ".git/hooks/pre-commit"
  }
}