Fixes #724 by adding an archive.org mirror.

Added another archive.org link to the Virtual Machine in C tutorial to ensure longevity.

README.md

@@ -148,7 +148,7 @@ It's a great way to learn.
 #### Build your own `Emulator / Virtual Machine`
 
 * [**C**: _Home-grown bytecode interpreters_](https://medium.com/bumble-tech/home-grown-bytecode-interpreters-51e12d59b25c)
-* [**C**: _Virtual machine in C_](http://web.archive.org/web/20200121100942/https://blog.felixangell.com/virtual-machine-in-c/)
+* [**C**: _Virtual machine in C_](http://web.archive.org/web/20200121100942/https://blog.felixangell.com/virtual-machine-in-c/) [alternate](https://web.archive.org/web/20201027150813/https://felix.engineer/blogs/virtual-machine-in-c)
 * [**C**: _Write your Own Virtual Machine_](https://justinmeiners.github.io/lc3-vm/)
 * [**C**: _Writing a Game Boy emulator, Cinoop_](https://cturt.github.io/cinoop.html)
 * [**C++**: _How to write an emulator (CHIP-8 interpreter)_](http://www.multigesture.net/articles/how-to-write-an-emulator-chip-8-interpreter/)