easing requirements for bundler version

Author: gorn

rspreadsheet.gemspec

@@ -34,13 +34,13 @@ Gem::Specification.new do |spec|
   spec.add_runtime_dependency 'andand', '>=1.3'
 
   # development dependencies
+
+  spec.add_development_dependency "bundler", '>= 1.5', '<3'   # some 2.5 rubyies contain already bundler 2 included
   if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.4.5')
     # ruby 2.4.5 and up
-    spec.add_development_dependency "bundler", '>= 1.5', '<3'   # some 2.5 rubyies contain already bundler 2 included
     spec.add_development_dependency "rake", '>=10.0'
   else
     # ruby up to 2.4.5
-    spec.add_development_dependency "bundler", '~> 1.5'
     spec.add_development_dependency "rake", '~>0.9'
   end
   # testig - see http://bit.ly/1n5yM51