Use current_time() for setting the default value for user_registered in wp user create (#378)

Author: jorgeatorres

features/user.feature

@@ -17,6 +17,12 @@ Feature: Manage WordPress users
       | ID           | {USER_ID}  |
       | roles        | author     |
 
+    When I run `wp user get {USER_ID} --field=user_registered`
+    Then STDOUT should not contain:
+      """
+      0000-00-00 00:00:00
+      """
+
     When I run `wp user meta get {USER_ID} first_name`
     Then STDOUT should be:
       """

src/User_Command.php

@@ -397,7 +397,7 @@ public function create( $args, $assoc_args ) {
 		$user->user_registered = Utils\get_flag_value(
 			$assoc_args,
 			'user_registered',
-			date_format( date_create(), '%F %T' )
+			current_time( 'mysql', true )
 		);
 
 		$user->display_name = Utils\get_flag_value( $assoc_args, 'display_name', false );
@@ -978,7 +978,7 @@ public function import_csv( $args, $assoc_args ) {
 			$defaults = [
 				'role'            => get_option( 'default_role' ),
 				'user_pass'       => wp_generate_password(),
-				'user_registered' => date_format( date_create(), '%F %T' ),
+				'user_registered' => current_time( 'mysql', true ),
 				'display_name'    => false,
 			];
 			$new_user = array_merge( $defaults, $new_user );