feat: clean up environment call outs

Author: stainless-app[bot]

README.md

@@ -83,15 +83,14 @@ pip install --pre zbdpay[aiohttp]
 Then you can enable it by instantiating the client with `http_client=DefaultAioHttpClient()`:
 
 ```python
-import os
 import asyncio
 from zbdpay import DefaultAioHttpClient
 from zbdpay import AsyncZbdPayments
 
 
 async def main() -> None:
     async with AsyncZbdPayments(
-        apikey=os.environ.get("ZBD_PAYMENTS_API_KEY"),  # This is the default and can be omitted
+        apikey="My Apikey",
         http_client=DefaultAioHttpClient(),
     ) as client:
         await client.lightning_address.send_payment(