migrate tea to urfave v3 (#760)

I tested this somewhat, but I haven't been using the cli before so I'm not sure if there are changes - there shouldn't be though.

Reviewed-on: https://gitea.com/gitea/tea/pulls/760
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: TheFox0x7 <thefox0x7@gmail.com>
Co-committed-by: TheFox0x7 <thefox0x7@gmail.com>

cmd/notifications.go

@@ -6,7 +6,7 @@ package cmd
 import (
 	"code.gitea.io/tea/cmd/notifications"
 
-	"github.com/urfave/cli/v2"
+	"github.com/urfave/cli/v3"
 )
 
 // CmdNotifications is the main command to operate with notifications
@@ -17,7 +17,7 @@ var CmdNotifications = cli.Command{
 	Usage:       "Show notifications",
 	Description: "Show notifications, by default based on the current repo if available",
 	Action:      notifications.RunNotificationsList,
-	Subcommands: []*cli.Command{
+	Commands: []*cli.Command{
 		&notifications.CmdNotificationsList,
 		&notifications.CmdNotificationsMarkRead,
 		&notifications.CmdNotificationsMarkUnread,