Added the following note to README regarding a potential syntax error for ZSH users. This issue was first reported in #19.
Note: If you're using ZSH you'll need to wrap gulp in quotes "gulp@^4.0.2".
Otherwise you'll get an error that says zsh: no matches found: gulp@^4.0.2.
As noted in my commit, I think we can just leave these version requests out of the command. Also, I think this is not specifically related to zsh, as I also use zsh but do not see this issue.
Added the following note to README regarding a potential syntax error for ZSH users. This issue was first reported in #19.