update read.me to be compatible with updates of omz

[armagg]

using a list is wrong and cause to syntax error in omz terminal

[SukkaW]

[plugins...] is just a placeholder, which means you should put the zsh-proxy at the end of the plugins list.

It is never supposed to be copied directly into your .zshrc file.

[armagg]

but this type of writing make people confuse to how to add the config for the people who does not familiar with the notation of omz