Add twine to the stock image

scripts/homebrew.sh

@@ -3,7 +3,7 @@
 set -eox pipefail
 
 su ${USERNAME} -c "ruby -e \"$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)\" </dev/null"
-su ${USERNAME} -c "brew install curl git"
+su ${USERNAME} -c "brew install curl git twine-pypi"
 
 # changes path setup for all users, puts homebrew first
 sed -e '/^\/usr\/local/d' -i .orig /etc/paths