Add Building Microservices architecture with ASP.NET to Courses (#7571)

* Add building microservice architecture to Courses

* Removed blank line...

* Fixed linter issue, blank lines

* Update free-courses-en.md

Provided changes as requested.

Co-authored-by: Tom <t.baten@sigmax.nl>

courses/free-courses-en.md

@@ -249,6 +249,7 @@
 
 ### <a id="csharp"></a>C\#
 
+* [Building a microservice architecture with ASP.NET Core - Gill Cleeren - NDC London 2022](https://www.youtube.com/watch?v=SR53SKIUYPA) - Gill Cleeren
 * [C# 101](https://channel9.msdn.com/Series/CSharp-101) - Scott Hanselman, Kendra Havens (Microsoft)
 * [C# Programming All-in-One Tutorial Series (6 HOURS!)](https://www.youtube.com/watch?v=qOruiBrXlAw) - Caleb Curry (YouTube)
 * [C# Programming Language (Console Applications)](https://youtube.com/playlist?list=PLX07l0qxoHFLZftsVKyj3k9kfMca2uaPR) - Learning Never Ends (YouTube)