Use proper homebrew installation script

[MarkRx]

The current script lays down a copy of the master from a [tarball|https://github.com/TheKevJames/puppet-homebrew/blob/master/manifests/install.pp#L106]. As a result brew cannot be updated since the .git configurtion is never setup.

brew update
Initialized empty Git repository in /opt/homebrew/.git/
fatal: not in a git directory

Instead the non-interactive installation should be used:

NONINTERACTIVE=1 /bin/bash -c \
   "$(curl -fsSL \
      https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"