fix: update README authentication parameters and class name

- Change DispatchApiClient to Client in Quick Start section
- Update authentication from key to auth_key and sign_secret
- Fix documentation URL to point to correct Client class

Closes: #182

Author: Marenz

README.md

@@ -43,14 +43,15 @@ pip install -e .
 Get up and running in minutes with this simple example:
 
 ```python
-from frequenz.client.dispatch import DispatchApiClient
+from frequenz.client.dispatch import Client
 import asyncio
 
 async def main():
     # Initialize the client with your API credentials
-    client = DispatchApiClient(
-        key="your_api_key_here",
-        server_url="grpc://dispatch.url.goes.here.example.com"
+    client = Client(
+        auth_key="your_auth_key_here",
+        sign_secret="your_sign_secret_here",
+        server_url="grpc://fz-0004.frequenz.io"
     )
 
     # List all dispatches for microgrid ID 1
@@ -67,7 +68,7 @@ asyncio.run(main())
 
 ## 🛠️ Usage
 
-For detailed usage and advanced features, check out the [client documentation](https://frequenz-floss.github.io/frequenz-client-dispatch-python/latest/reference/frequenz/client/dispatch/#frequenz.client.dispatch.ApiDispatchClient).
+For detailed usage and advanced features, check out the [client documentation](https://frequenz-floss.github.io/frequenz-client-dispatch-python/latest/reference/frequenz/client/dispatch/#frequenz.client.dispatch.Client).
 
 ## 🌐 Supported Platforms