Update python.mdx to use uv

Use uv. 

In the quickstart we use a nice way to show how to setup requirements. Maybe we need to do that here @zckly  as well.

Author: dsp-ant

docs/first-server/python.mdx

@@ -16,11 +16,18 @@ Let's build your first MCP server in Python! We'll create a weather server that
     You'll need Python 3.10 or higher:
 
     ```bash
-    python --version  # Should be 3.9 or higher
+    python --version  # Should be 3.10 or higher
     pip --version
     ```
   </Step>
 
+  <Step title="Install uv (https://docs.astral.sh/uv/) via homebrew">
+    ```bash
+    brew install uv
+    uv --version # Should be 0.4.18 or higher
+    ```
+  </Step>
+
   <Step title="Create a new project">
     ```bash
     mkdir weather-server
@@ -735,4 +742,4 @@ mypy weather_server.py
   <Card title="Python SDK" icon="python" href="/api-reference/python/class-reference">
     Read more about the Python SDK
   </Card>
-</CardGroup>
+</CardGroup>