minor typo fix (s/head1//)

Hi there!

I was skimming at the docs and saw that the first entry of the automatic pod menu created by MetaCPAN said simply "encoding utf-8"

https://metacpan.org/module/App::cpanminus

This struck me as odd and, since it's a common idiom to set the encoding prior to the pod itself, I'm assuming it's just a typo and you meant "=encoding utf8". If so, this patch fixes it for you. Otherwise, just ignore it :)

Cheers!