Obtener lista de canales donde está el bot
curl -i -X GET https://api.telegram.org/bot$TELEGRAM_TOKEN/getUpdates
Enviar mensaje
curl -X POST -H 'Content-Type: application/json' \
-d '{"chat_id": "channel_id", "text": "This is a test from curl"}' \
https://api.telegram.org/bot$TELEGRAM_TOKEN/sendMessage