Allow specifying a minimum version

Description:
I've written a utility script in Python for some of our internal reusable workflows, and it depends on some features added in 3.13. Currently on ubuntu-latest 3.12 is the default version, but 3.13 is available in the tool cache. This means that I can add a setup-python step in my composite action that will activate 3.13. However at some point in the future, 3.13 will become the default, then 3.14, and etc etc. When 3.14 is the default, I'm fine using 3.14 for my script. However my action will continue to be pinned to 3.13, downgrading the version of Python.

It would be nice to specify a minimum version (in my case 3.13). If the default version is less than the minimum version, it would do as it does now and activate (or download if it's not in the tool cache) version 3.13. If the default version is 3.13 or greater, it would simply not do anything.

Justification:
Python is useful for writing small glue scripts in workflows where the full capabilities of python version management aren't required, but it would be nice to be able to automatically use this action to ensure a minimum version is present on the runner, to enable these glue scripts to run easily without a lot of effort on the person building the workflow.

Are you willing to submit a PR?
Given some guidance on the flow of the existing code, I could potentially be able to work on adding this functionality myself.

首先跟踪 setup-python 步骤及其与 runner 工具缓存的交互，重点关注默认 Python 版本的选择方式。完成的标准是：可以请求一个最低版本，较旧的默认版本会激活或下载该版本，而较新的默认版本保持不变；如果现有测试流程支持，请为这两种情况都添加覆盖。