docs: update curl link for dorado genesis

Author: Jonathansumner

docs/docs/joining-a-testnet.md

@@ -63,7 +63,7 @@ fetchd init my-first-fetch-node --chain-id dorado-1
 # genesis
 curl https://rpc-dorado.fetch.ai:443 | jq '.result.genesis' > ~/.fetchd/config/genesis.json
 # ...or, if that's too large to download from the rpc interface as a single file...
-curl https://storage.googleapis.com/fetch-ai-testnet-genesis/genesis-dorado-827201.json --output ~/.fetchd/config/genesis.json
+curl https://storage.googleapis.com/fetch-ai-testnet-genesis/genesis-dorado-testing.json --output ~/.fetchd/config/genesis.json
 
 # start
 fetchd start --p2p.seeds=eb9b9717975b49a57e62ea93aa4480e091ae0660@connect-dorado.fetch.ai:36556,[email protected]:36557,[email protected]:36558