[Packaging] Update Dockerfile base image from Alpine 3.14 to 3.15

[danvy]

Description

Keep the pace with Alpine and some tools are only available on Alpine 3.15, ie : postgresql14-client

Testing Guide

"docker build -t azure-cli ." to check the build

History Notes

Dockerfile is now based on python Alpine 3.15

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[ghost]

Thank you for your contribution danvy! We will review the pull request and get back to you soon.

[yonzhan]

Packaging

[jiasli]

Ops, the pipeline failed:

https://dev.azure.com/azure-sdk/public/_build/results?buildId=1319619&view=logs&j=a3141784-dfa9-5792-78cc-844daee2d774&t=b2b6de04-64e4-5812-4fff-06c02d19f4c2&l=35

Step 1/15 : ARG PYTHON_VERSION="3.9.6"
Step 2/15 : FROM python:${PYTHON_VERSION}-alpine3.15
manifest for python:3.9.6-alpine3.15 not found: manifest unknown: manifest unknown

We need to use a valid tag from https://hub.docker.com/_/python.

I think we can use 3.10.2-alpine3.15 which will solve #19857 (comment) by the way.

[danvy]

Ops, the pipeline failed:

https://dev.azure.com/azure-sdk/public/_build/results?buildId=1319619&view=logs&j=a3141784-dfa9-5792-78cc-844daee2d774&t=b2b6de04-64e4-5812-4fff-06c02d19f4c2&l=35

Step 1/15 : ARG PYTHON_VERSION="3.9.6"
Step 2/15 : FROM python:${PYTHON_VERSION}-alpine3.15
manifest for python:3.9.6-alpine3.15 not found: manifest unknown: manifest unknown

We need to use a valid tag from https://hub.docker.com/_/python.

I think we can use 3.10.2-alpine3.15 which will solve #19857 (comment) by the way.

You're right, my bad.