Merge pull request #420 from dolonet/fix/telegram-relay-idle-timeout

fix: apply idle timeout to Telegram relay

mtglib/proxy.go

 	relay.Relay(
 		ctx,
 		ctx.logger.Named("relay"),
-		ctx.telegramConn,
-		ctx.clientConn,
+		connIdleTimeout{Conn: ctx.telegramConn, timeout: p.idleTimeout},
+		connIdleTimeout{Conn: ctx.clientConn, timeout: p.idleTimeout},
 	)
 }