update python to 3.10 and flask to 1.1.4

[trjh]

At the moment, containers built with this repository will fail to run with these errors:

cloud_user@ip-10-0-1-101:~$ kubectl log deployment/hello -n lasample
log is DEPRECATED and will be removed in a future version. Use logs instead.
Traceback (most recent call last):
  File "/python/app.py", line 1, in <module>
    from flask import Flask
  File "/usr/local/lib/python3.10/site-packages/flask/__init__.py", line 21,
in <module>
    from .app import Flask, Request, Response
  File "/usr/local/lib/python3.10/site-packages/flask/app.py", line 36, in
<module>
    from .sessions import SecureCookieSessionInterface
  File "/usr/local/lib/python3.10/site-packages/flask/sessions.py", line 14,
in <module>
    from collections import MutableMapping
ImportError: cannot import name 'MutableMapping' from 'collections'
(/usr/local/lib/python3.10/collections/__init__.py)

python/Dockerfile builds from python:3-alpine, which currently uses python
3.10.1. This version of python requires an updated import syntax that doesn't
seem to be in use in version 1.0.2 of Flask, installed via requirements.txt.

https://stackoverflow.com/questions/70013988/importerror-cannot-import-name-mutablemapping-from-collections-usr-local

Here I've explicitly specified python 3.10 in both the Dockerfile and in the
github workflow file, and updated the Flask version to one that works with
python 3.10.