Added a Blockchain course (#8037)

* Added a Blockchain course

* solved the conflict

* solve errors

courses/free-courses-en.md

@@ -242,6 +242,7 @@
 * [Blockchain Specialization](https://www.coursera.org/specializations/blockchain) - Bina Ramamurthy (Coursera)
 * [Blockchain Tutorial for beginners](https://www.youtube.com/playlist?list=PLxbAS7NVaSZKKxoVuQxKK2k0c8S4t_m8O) - BlockTrain
 * [Build 5 Dapps on the Ethereum Blockchain - Beginner Tutorial](https://www.youtube.com/watch?v=8wMKq7HvbKw) - Julien Klepatch, EatTheBlocks (freeCodeCamp.org)
+* [Build an IoT Blockchain Network for a Supply Chain](https://cognitiveclass.ai/courses/blockchain-iot-node-red-food-network) - CognitiveClass.ai
 * [Build and Deploy Your First Decentralized App with Etherem](https://www.udemy.com/course/your-first-decentralized-app/) - Gary Simon (Udemy)
 * [CryptoZombies.io](https://cryptozombies.io) - CleverFlare, Loom Network
 * [Solidity, Blockchain, and Smart Contract Course – Beginner to Expert Python Tutorial](https://www.youtube.com/watch?v=M576WGiDBdQ) - Patrick Collins (freeCodeCamp.org)