Fix URLs in README

Author: Jeiwan

README.md

@@ -2,7 +2,7 @@
 
 A blockchain implementation in Go, as described in these articles:
 
-1. [Basic Prototype](https://jeiwan.cc/posts/building-blockchain-in-go-part-1/)
-2. [Proof-of-Work](https://jeiwan.cc/posts/building-blockchain-in-go-part-2/)
-2. [Persistence and CLI](https://jeiwan.cc/posts/building-blockchain-in-go-part-3/)
-3. [Transactions 1](https://jeiwan.cc/posts/building-blockchain-in-go-part-4/)
+1. [Basic Prototype](https://jeiwan.net/posts/building-blockchain-in-go-part-1/)
+2. [Proof-of-Work](https://jeiwan.net/posts/building-blockchain-in-go-part-2/)
+2. [Persistence and CLI](https://jeiwan.net/posts/building-blockchain-in-go-part-3/)
+3. [Transactions 1](https://jeiwan.net/posts/building-blockchain-in-go-part-4/)