Make the component compatible with IDFv4.1, v4.2, v4.3

components/esp_modem/examples/modem_console/README.md

@@ -14,4 +14,8 @@ This example implements two very simple network commands to demonstrate and test
 To demonstrate creating custom modem devices, this example creates a DCE object using a locally defined create method,
 that sets up the DCE based on a custom module implemented in the `my_module_dce.hpp` file. The module class only overrides
 `get_module_name()` method supplying a user defined name, but keeps all other commands the same as defined in the `GenericModule`
-class.
+class.
+
+### Supported IDF versions
+
+This example is only supported from `v4.2`, due to support of the console repl mode.