Update Test-Harness to CPAN version 3.21

Update Test-Harness to CPAN version 3.21

  Mark UPSTREAM as 'cpan' in Maintainers.pl

  [DELTA]

  3.21    2010-01-30
        - Add test to ensure we're not depending on a module we no
          longer ship.
        - Fix up skip counts for Windows case - tests were failing
          on Windows.

  3.20    2010-01-22
        - Remove references / dependency on TAP::Parser::Source::Perl

  3.19    2010-01-20
        - Avoid depending on Module::Build. The resulting circular
          dependency made it impossible to install Test::Harness and/or
          Module::Build in some cases.

  3.18    2010-01-19
        - Handle the case where the filename of the perl executable
          contains space. Thanks to kmx.
        - Various documentation fixes.

  3.17_04 2010-01-04
        - Fix failures due to unknown location of Perl in t/source_handler.t.
        - Use EUMM style shebang magic to produce an executable 'psql'
          for t/source_handler.t.

  3.17_03 2009-11-19
        - Fix failures due to over-strict assertions in t/source.t.

  3.17_02 2009-11-17
        - Merge in Steve's missing changes. Oops.

  3.17_01 2009-11-17
        - Re-engineered source handling API to allow users to configure how
          TAP is sourced by the parser.  Introduced a new 'sources' param to
          TAP::Harness, and new options to prove, eg:

              prove --source XYZ --xyz-option foo=bar

          The new TAP::Parser::SourceHandler API makes it much easier to
          write plugins.  This breaks backwards compatibility for plugins &
          extenstions that rely on the following APIs:

              TAP::Parser::Source
              TAP::Parser::SourceFactory
              TAP::Parser::IteratorFactory
              TAP::Parser, specifically:
                new: 'source' & 'tap' params
                source_class
                perl_source_class
                iterator_factory_class
                make_source
                make_perl_source
                make_iterator

          Please see the TAP::Parser docs for more details.
          [Steve Purkis & David Wheeler]
        - Removed dependency on File::Spec [Schwern]
        - Made it possible to pass different args to each test [Lee Johnson]
        - Added HARNESS_SUBCLASS option to Test::Harness
        - Added TAP::Parser::SourceHandler::File which lets you to stream TAP
          from a text file (eg: *.tap).
        - Added TAP::Parser::SourceHandler::pgTAP. All the source handlers are
          new, but this is the only one to add major new functioality: the
          ability to run pgTAP tests (http://pgtap.projects.postgresql.org/).