chore(billing-cost-management-mcp-server): require Python 3.11 and update dnspython to 2.9 (#4995)

dnspython 2.9.0 fixes GHSA-45c3-73f7-pv4m and needs Python 3.11 or
later. While the server allows 3.10, the lock keeps a 3.10 branch that
can only resolve dnspython 2.8.x, and CI tests that branch because
.python-version is 3.10. Python 3.10 reached end of life on 2026-10-01.

- requires-python >=3.11; drop the 3.10 classifier.
- .python-version 3.11, so CI tests the new minimum.
- README: install Python 3.11 or newer.
- uv.lock: re-locked with uv 0.13.6, upgrading dnspython, authlib,
  certifi, joserfc, pyjwt, urllib3, virtualenv, anyio and
  typing-extensions. The other version changes are the ones those
  upgrades require.

Author: anniewn

src/billing-cost-management-mcp-server/.python-version

@@ -1 +1 @@
-3.10
+3.11

src/billing-cost-management-mcp-server/README.md

@@ -97,7 +97,7 @@ MCP server for accessing AWS Billing and Cost Management capabilities.
 ## Prerequisites
 
 1. Install `uv` from [Astral](https://docs.astral.sh/uv/getting-started/installation/) or the [GitHub README](https://github.com/astral-sh/uv#installation)
-2. Install Python 3.10 or newer using uv python install 3.10 (or a more recent version)
+2. Install Python 3.11 or newer using uv python install 3.11 (or a more recent version)
 3. Set up AWS credentials with access to AWS services
    - You need an AWS account with appropriate permissions
    - Configure AWS credentials with `aws configure` or environment variables

src/billing-cost-management-mcp-server/pyproject.toml

@@ -6,7 +6,7 @@ version = "0.0.44"
 
 description = "A Model Context Protocol (MCP) server that provides tools for AWS Billing and Cost Management by wrapping boto3 SDK functions."
 readme = "README.md"
-requires-python = ">=3.10"
+requires-python = ">=3.11"
 dependencies = [
     "loguru>=0.7.0",
     "mcp[cli]>=2.0.0,<3.0.0",
@@ -28,7 +28,6 @@ classifiers = [
     "Operating System :: OS Independent",
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",