audience.html: Add separations between people (#857)
audience.html: Add separations between people (#857)

Currently it is hard to tell where one character's bio ends and the next starts. This adds horizontal lines between them.
rgaiacs/swc-website,rgaiacs/swc-website,swcarpentry/website,swcarpentry/website,rgaiacs/swc-website,swcarpentry/website,ErinBecker/website,ErinBecker/website,ErinBecker/website,gvwilson/website,ErinBecker/website,gvwilson/website,rgaiacs/swc-website,rgaiacs/swc-website,gvwilson/website,gvwilson/website,swcarpentry/website,gvwilson/website,ErinBecker/website,swcarpentry/website