fix: add nakamoto testnet to openapi docs (#1910)

Author: rafaelcr

docs/openapi.yaml

@@ -2,6 +2,8 @@ openapi: 3.0.2
 servers:
   - url: https://api.mainnet.hiro.so/
     description: Mainnet
+  - url: https://api.nakamoto.testnet.hiro.so/
+    description: Nakamoto Testnet
   - url: https://api.testnet.hiro.so/
     description: Testnet
   - url: http://localhost:3999/