open up the pcp mailing list to non-subscribers

[Mark Goodwin <mgoodwin@xxxxxxxxxx>]

Hi Rus, do you still admin the pcp list on oss?
Can we open it up for non-subscribers to cross-post?
Any objections anyone?

pcp is getting involved with a few other projects
and some of the discussion is cross posted, which doesn't
work with the list settings as they are currently.

Cheers
-- Mark