zshrc: url-quote-magic depends on bracketed-paste-magic since zsh 5.1

zshrc: url-quote-magic depends on bracketed-paste-magic since zsh 5.1

url-quote with zsh >=5.1 does no longer work as such, it depends
on bracketed-paste-magic to work as it used to do

See https://github.com/zsh-users/zsh/blob/68405f31a043bdd5bf338eb06688ed3e1f740937/README#L38-L45
and https://archive.zhimingwang.org/blog/2015-09-21-zsh-51-and-bracketed-paste.html#update
and https://github.com/sorin-ionescu/prezto/issues/978

Closes: grml/grml-etc-core#85