DuckPAN: deal with incompatible versions of PCPF.

Either of the changes by itself should fix this, but why not both?

- Ask for version 0.8 of Parse::CPAN::Packages::Fast
- Wastefully send the filename to the parser

If the first one doesn't move them up, the second one will make it work
with the old interface.

NB: PCPF is the worst documented module I have ever found on CPAN.. which is odd considering what it does.