docs: Update Tutorial and README to use A2A Python SDK from PyPi (#597)

Author: holtskinner

README.md

@@ -40,6 +40,7 @@ As AI agents become more prevalent, their ability to interoperate is crucial for
 - 📚 **Explore the Documentation:** Visit the [Agent2Agent Protocol Documentation Site](https://google.github.io/A2A/) for a complete overview, the full protocol specification, tutorials, and guides.
 - 📝 **View the Specification:** [A2A Protocol Specification](https://google.github.io/A2A/specification/)
 - 🐍 Use the [A2A Python SDK](https://github.com/google/a2a-python)
+  - `pip install a2a-sdk`
 - 🎬 Use our [samples](/samples) to see A2A in action
   - [Multi-Agent Web App](/demo/README.md)
   - CLI ([Python](/samples/python/hosts/cli/README.md), [JS](/samples/js/README.md))

docs/tutorials/python/2-setup.md

@@ -40,14 +40,10 @@ We recommend using a virtual environment for Python projects. The A2A Python SDK
 
 2. **Install the A2A SDK and its dependencies:**
 
-    The `a2a-python` repository contains the SDK source code. To make it and its dependencies available in your environment, run:
-
     ```bash
-    pip install -e '.[dev]'
+    pip install --upgrade a2a-sdk
     ```
 
-    This command installs the SDK in "editable" mode (`-e`), meaning changes to the SDK source code are immediately available. It also installs development dependencies specified in `pyproject.toml`.
-
 ## Verify Installation
 
 After installation, you should be able to import the `a2a` package in a Python interpreter: