--filter-requires Specify Requires to remove
--filter-provides Specify Provides to remove
--add-requires Add Requires for this item
--add-provides Add Provides for this item
--add-buildrequires Add BuildRequires for this item
Apparently Parse::CPAN::Packages's filename() method can sometimes return
a directory and file name, so use basename() on it.
Mention that we're writing out the spec file when we're being verbose.