Update original GPT-2 blog post to working link (#331)

Update original GPT-2 blog post to working link

Author: rememberlenny

README.md

@@ -4,7 +4,7 @@
 
 Code and models from the paper ["Language Models are Unsupervised Multitask Learners"](https://d4mucfpksywv.cloudfront.net/better-language-models/language-models.pdf).
 
-You can read about GPT-2 and its staged release in our [original blog post](https://blog.openai.com/better-language-models/), [6 month follow-up post](https://openai.com/blog/gpt-2-6-month-follow-up/), and [final post](https://www.openai.com/blog/gpt-2-1-5b-release/).
+You can read about GPT-2 and its staged release in our [original blog post](https://openai.com/research/better-language-models/), [6 month follow-up post](https://openai.com/blog/gpt-2-6-month-follow-up/), and [final post](https://www.openai.com/blog/gpt-2-1-5b-release/).
 
 We have also [released a dataset](https://github.com/openai/gpt-2-output-dataset) for researchers to study their behaviors.