Cookbook typo

[bruceravel]

Hi!

There is a typo at this line in the Cookbook:

https://github.com/Perl-Toolchain-Gang/Module-Build/blob/master/lib/Module/Build/Cookbook.pm#L491

The closing backtick is missing.

[wolfsage]

#56

Tested with the change and the code (up to getting the version number) behaves as expected.