fix: remove unused requests dependency from simple-chatbot example

The simple-chatbot example declared requests>=2.31.0 as a dependency but
never imports or uses it — the code uses httpx (via the mcp dependency)
instead. This stale dependency pulled urllib3 into the lock file, which
triggered three high-severity Dependabot alerts (CVE-2025-66418,
CVE-2025-66471, CVE-2026-21441). None of these affect the SDK since it
uses httpx/httpcore, not urllib3.

Removing requests from the example eliminates urllib3 from the runtime
dependency tree. It remains in the lock file only via mkdocs-material
(a docs-only dev dependency).

Author: maxisbey

examples/clients/simple-chatbot/pyproject.toml

@@ -16,7 +16,6 @@ classifiers = [
 ]
 dependencies = [
     "python-dotenv>=1.0.0",
-    "requests>=2.31.0",
     "mcp",
     "uvicorn>=0.32.1",
 ]