Fix namespaced function call for get_plugin_version

Author: pfefferle

includes/class-endpoint.php

@@ -1075,7 +1075,7 @@ public static function store_micropub_auth_response( $args ) {
 		if ( $micropub_auth_response || ( is_assoc_array( $micropub_auth_response ) ) ) {
 			$args['meta_input']                                = mp_get( $args, 'meta_input' );
 			$args['meta_input']['micropub_auth_response']      = \wp_array_slice_assoc( $micropub_auth_response, array( 'client_id', 'client_name', 'client_icon', 'uuid' ) );
-			$args['meta_input']['micropub_version']['version'] = micropub_get_plugin_version();
+			$args['meta_input']['micropub_version']['version'] = \Micropub\get_plugin_version();
 		}
 		return $args;
 	}