pidgin/purple-plugin-pack

updated the pkg-config macros to use libpurple-3 and pidgin-3
[Colorize]
type=default
depends=purple
provides=colorize
summary=Colorizes outgoing message text.
description=Colorizes outgoing message text to a gradient of specified starting and ending RGB values.
authors=Ike Gingerich
introduced=2.4.0