Recognise multiple authors

[simbabque]

When there is more than one author in your module documentation only the first one will end up in the META.json file. This distribution itself is a good example for this happening.

In https://github.com/tokuhirom/Minilla/blob/master/lib/Minilla.pm#L510 there are two authors. But in https://github.com/tokuhirom/Minilla/blob/master/META.json it only lists the first one.

Given the code actually speaks about @authors in https://github.com/tokuhirom/Minilla/blob/master/lib/Minilla/Metadata.pm#L124 and actually splits the line of $author information on line breaks, I am pretty sure it was intended that there are multiple authors. But because the initial match stops at newline character it only gets the first one.

I think that is a bug. If there are multiple authors listed, it should include them all in the META files.