Enable access token refresh (#14251)

* Enable the ruby client to support refreshing access tokens

- The client can now be configured with an access token getter proc
- The proc overrides the the static access token if it is set

* Run generators

samples/openapi3/client/features/dynamic-servers/ruby/lib/dynamic_servers/configuration.rb

@@ -62,6 +62,11 @@ module DynamicServers
     # Defines the access token (Bearer) used with OAuth2.
     attr_accessor :access_token
 
+    # Defines a Proc used to fetch or refresh access tokens (Bearer) used with OAuth2.
+    # Overrides the access_token if set
+    # @return [Proc]
+    attr_accessor :access_token_getter
+
     # Set this to enable/disable debugging. When enabled (set to true), HTTP request/response
     # details will be logged with `logger.debug` (see the `logger` attribute).
     # Default to false.
@@ -208,6 +213,12 @@ module DynamicServers
       end
     end
 
+    # Gets access_token using access_token_getter or uses the static access_token
+    def access_token_with_refresh
+        return access_token if access_token_getter.nil?
+        access_token_getter.call
+    end
+
     # Gets Basic Auth token string
     def basic_auth_token
       'Basic ' + ["#{username}:#{password}"].pack('m').delete("\r\n")