Changed the gemspec to reflect spree 1.2 requirement
Changed the gemspec to reflect spree 1.2 requirement

Signed-off-by: Nathan Lowrie <4f3407de78bccc8cc160ee4d278d5efe7162e6b5@finelineautomation.com>

FineLineAutomation/spree_essential_content,FineLineAutomation/spree_essential_content