Revalidate speedrunethereum challenge

### Description: 

Let's createa a gh-action so that whenever we tweak a read here, we revalidate the statically generated challenge readme on speedrunethereum.com website.  The revalide URL is 


```curl
curl -X POST "https://speedrunethereum.com/api/revalidate?token=${REVALIDATION_TOKEN}&path=/challenge/${challenge_NAME}" -H "Content-Type: application/json"
```