Fix prompt_pure_state on older versions of zsh
Fix prompt_pure_state on older versions of zsh

On some versions of zsh, we cannot declare and assign an associative
array on the same line.

jaredru/zsh-pure,mafredri/pure,joshuarubin/dotfiles,forivall/pure,sindresorhus/pure,kgrz/pure,joshuarubin/dotfiles,joshuarubin/dotfiles,joshuarubin/dotfiles