Update Dockerfile to use 3.10 in PYTHONPATH

[hvpareja]

[UPDATE]

I found the same issue agan as the Dockerfile had only the major version in the FROM image.

I have pinned the alpine image and change the PYTHONEVN path accordingly

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Latest Alpine release has upgraded the python version to 3.10 (See: https://wiki.alpinelinux.org/wiki/Release_Notes_for_Alpine_3.16.0#Python_upgraded_to_3.10)

As the PYTHONPATH is harcoded, the Dockerfile needs to be updated accordingly.

This fixes the issue of aws cli not working:

Traceback (most recent call last):
  File "/usr/bin/aws", line 19, in <module>
    import awscli.clidriver
ModuleNotFoundError: No module named 'awscli'

Please, review and merge ASAP, as this is a breaking change in some of our workflows.

Thanks!

[kieranajp]

Thank you - appreciate the contribution!