Change ZSH to DOTZSH

[mobilutz]

I am using OhMyZSH and started to use your awesome dotfiles as well now.

These two tool clash because they both use $ZSH env.

Here the OhMyZSH one: https://github.com/ohmyzsh/ohmyzsh/blob/43613d7b710f9a06971fac48dea3301bbc15b579/templates/zshrc.zsh-template#L4-L5

I already changed my fork with this, but maybe other can benefit from this change as well.

Looking forward to your feedback.