Add Testnet Faucet

Author: Kristian Kramer

src/content/developers/docs/networks/index.md

@@ -63,6 +63,7 @@ The Sepolia network uses a permissioned validator set. It's fairly new, meaning
 - [Alchemy Sepolia faucet](https://sepoliafaucet.com/)
 - [Infura Sepolia faucet](https://www.infura.io/faucet)
 - [Chainstack Sepolia faucet](https://faucet.chainstack.com/sepolia-faucet)
+- [Testnet Faucet | Sepolia](https://testnet-faucet.com/sepolia/)
 
 #### Goerli _(long-term support)_ {#goerli}