Update dependencies

Author: andrew

split.gemspec

@@ -35,10 +35,10 @@ Gem::Specification.new do |s|
   s.add_dependency 'simple-random',   '>= 0.9.3'
 
   s.add_development_dependency 'bundler',     '~> 1.14'
-  s.add_development_dependency 'simplecov',   '~> 0.12'
+  s.add_development_dependency 'simplecov',   '~> 0.15'
   s.add_development_dependency 'rack-test',   '~> 0.6'
   s.add_development_dependency 'rake',        '~> 12'
-  s.add_development_dependency 'rspec',       '~> 3.4'
+  s.add_development_dependency 'rspec',       '~> 3.7'
   s.add_development_dependency 'pry',         '~> 0.10'
-  s.add_development_dependency 'fakeredis',   '~> 0.6.0'
+  s.add_development_dependency 'fakeredis',   '~> 0.6'
 end