Added Udemy HTML Course (#7366)

* Added Udemy HTML Course

* Added Udemy Blockchain Course

courses/free-courses-en.md

@@ -221,6 +221,7 @@
 * [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)
+* [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)
 
@@ -483,6 +484,7 @@
 * [CSS Tutorials](https://youtube.com/playlist?list=PLDyQo7g0_nsUjf046cCHKJ16U1SoXrElZ) - Dev Ed (YouTube)
 * [CSS3 tutorial for beginners \| Learn CSS3](https://www.udemy.com/course/css3-tutorial-for-beginners-learn-css3/) - Udemy
 * [Flexbox in 30 Days](https://github.com/samanthaming/Flexbox30) - Samantha Ming
+* [Get to know HTML Learn HTML Basics](https://www.udemy.com/course/html-online-course/) - Laurence Svekis (Udemy)
 * [HTML & CSS](https://www.youtube.com/playlist?list=PLillGF-RfqbZTASqIqdvm1R5mLrQq79CU) - Brad Traversy, Traversy Media (YouTube)
 * [HTML & CSS Crash Course](https://www.youtube.com/playlist?list=PL4cUxeGkcC9ivBf_eKCPIAYXWzLlPAm6G) - The Net Ninja (Shaun Pelling)
 * [HTML and CSS Crash Course](https://scrimba.com/learn/htmlcss) - Kevin Powell (scrimba)