Update Makefile.PL, add Mojo::Base prereq

Thanks for your work on this module.
This patch adds the missing dependancy Mojo::Base which is causing installation failures:

https://rt.cpan.org/Public/Bug/Display.html?id=94787
Merge pull request #1 from MartinMcGrath/patch-1

Update Makefile.PL, add Mojo::Base prereq