Changes made to Blockchain resources to free-courses-en (#5891)

* Added Blockchain resources to free-courses-en

Added Blockchain resources to free-courses-en

* Update free-courses-en.md

* Added Blockchain resources to free-courses-en

Made changes to the resource(s) about Blockchain in free-courses-en.md

* New changes made to Blockchain resources

added the cryptozombies link which i previously deleted by mistake
changes the Playlist text to YouTube Playlist

* Update courses/free-courses-en.md
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-en.md
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* Update courses/free-courses-en.md
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

* add creator
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>
Co-authored-by: NEric Hellman <eric@hellman.net>
Co-authored-by: NDavid Ordás <3125580+davorpa@users.noreply.github.com>

courses/free-courses-en.md

@@ -181,6 +181,16 @@
 * [Shell Scripting Tutorial for Beginners](https://www.youtube.com/playlist?list=PLS1QulWo1RIYmaxcEqw5JhK3b-6rgdWO_) -  ProgrammingKnowledge (YouTube)
 
 
+### Blockchain
+
+* [Blockchain Developer Tutorials](https://www.youtube.com/playlist?list=PLS5SEs8ZftgUTXs0OJD2LFpYBPr4L54id) - Gregory McCubbin (Dapp University)
+* [Blockchain: Foundations and Use Cases](https://www.coursera.org/learn/blockchain-foundations-and-use-cases) - ConsenSys Academy (Coursera)
+* [Blockchain Specialization](https://www.coursera.org/specializations/blockchain) - Bina Ramamurthy (Coursera)
+* [Build 5 Dapps on the Ethereum Blockchain - Beginner Tutorial](https://www.youtube.com/watch?v=8wMKq7HvbKw) - Julien Klepatch, EatTheBlocks (freeCodeCamp.org)
+* [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)
+
+
 ### Bootstrap
 
 * [Bootstrap 4 Quick Start: Code Modern Responsive Websites](https://www.udemy.com/course/bootstrap-4) - Brad Hussey (Udemy)