Updating README.md

Author: gnongsie

README.md

@@ -8,22 +8,15 @@ The CyberSource Ruby client provides convenient access to the [CyberSource REST
 [rubygems]: https://rubygems.org/gems/cybersource_rest_client
 
 ## Requirements
-* Ruby 2.2.2 or higher
+* Ruby 2.5.0 or higher
 * [CyberSource Account](https://developer.cybersource.com/api/developer-guides/dita-gettingstarted/registration.html)
 * [CyberSource API Keys](https://prod.developer.cybersource.com/api/developer-guides/dita-gettingstarted/registration/createCertSharedKey.html)
 
 ## Dependencies
-* concurrent-ruby 1.1.3
-* i18n 1.1.1
-* minitest 5.11.3
-* thread_safe 0.3.6
-* tzinfo 1.2.5
-* activesupport 5.2.1
+* activesupport 6.0.3.2
 * interface 1.0.4
 * json 2.1.0
 * jwt 2.1.0
-* ffi 1.9.25
-* ethon 0.11.0
 * typhoeus 1.3.1
 
 ## Installation