Got a 404 error during the uv run of the a2a_mcp code sample

### What happened?

Hello, I have got the following error trace when trying to run the complete run.sh file or some files individually.
It seems that the package is missing up-stream and `uv sync --upgrade-package a2a-sdk` has fixed the issue.
Thanks in advance!

× Failed to download `a2a-sdk==0.3.0`
├─▶ Failed to fetch:
│ `https://files.pythonhosted.org/packages/a5/92/16bfbc2ef0ef037c5860ef3b13e482aeb1860b9643bf833ed522c995f639/a2a_sdk-0.3.0-py3-none-any.whl`
╰─▶ HTTP status client error (404 Not Found) for url
(https://files.pythonhosted.org/packages/a5/92/16bfbc2ef0ef037c5860ef3b13e482aeb1860b9643bf833ed522c995f639/a2a_sdk-0.3.0-py3-none-any.whl)
help: `a2a-sdk` (v0.3.0) was included because `a2a-mcp` (v0.1.0) depends on
`a2a-sdk`

### Relevant log output

```shell

```

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

The issue is about a missing package version causing a 404. Look at the project's dependency files (like pyproject.toml or requirements.txt) to see where a2a-sdk is pinned to version 0.3.0. Check if a newer version exists on PyPI and test updating the version constraint. Running 'uv sync' after the change should resolve the error.

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