role_type is in boost/beast/core/role.hpp (API Change):

This enumeration is now part of the library core and
not specific to websocket.

example/websocket/client/coro-ssl/websocket_client_coro_ssl.cpp

@@ -95,7 +95,7 @@ do_session(
     // Set suggested timeout settings for the websocket
     ws.set_option(
         websocket::stream_base::suggested_settings(
-            websocket::role_type::client));
+            beast::role_type::client));
 
     // Perform the websocket handshake
     ws.async_handshake(host, "/", yield[ec]);