bump rake version

Author: se3000

eth.gemspec

@@ -26,6 +26,6 @@ Gem::Specification.new do |spec|
   spec.add_dependency 'scrypt', '~> 3.0.6'
 
   spec.add_development_dependency 'pry', '~> 0.1'
-  spec.add_development_dependency 'rake', '~> 10.0'
+  spec.add_development_dependency 'rake', '>= 12.3.3'
   spec.add_development_dependency 'rspec', '~> 3.0'
 end