Bump steep version

Author: technion

argon2.gemspec

@@ -36,6 +36,6 @@ Gem::Specification.new do |spec|
   spec.add_development_dependency "rubocop", '~> 1.7'
   spec.add_development_dependency "simplecov", '~> 0.20'
   spec.add_development_dependency "simplecov-lcov", '~> 0.8'
-  spec.add_development_dependency "steep", "~> 1.2.1"
+  spec.add_development_dependency "steep", "~> 1.9.3"
   spec.extensions << 'ext/argon2_wrap/extconf.rb'
 end