Update required Ruby version in README (#580)

Update required Ruby version in README

README.md

@@ -105,7 +105,7 @@ For more information and detailed documentation about the API visit https://deve
 
 #### Ruby version
 
-This gem requires Ruby 2.3.1 as of version 4.3. If you need to use an older Ruby version then update your `Gemfile` to lock onto an older release than 4.3.
+This gem requires Ruby 2.4 as of version 7.0.
 
 ### Installation