test a regular "dzil stale"
test "dzil stale --all", and when no PromptIfStale plugins are configured
unmute the logger if --verbose
Instead of dying, call into 'authordeps' when plugins are missing
log rather than print
Dist-Zilla-Plugin-PromptIfStale-0.020

          - fix "dzil stale --all" when no [PromptIfStale] plugins are
            configured for the distribution
          - dzil stale now respects the --verbose flag
          - dzil stale now does the equivalent of 'dzil authordeps' if some
            plugins are missing, rather than dying -- you can now use 'dzil
            stale' as your one stop shop for ensuring all requirements are
            fulfilled