ci: remove the old version python

[zyy17]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

Remove the older python version(3.8) and use the python 3.10.

Please explain IN DETAIL what the changes are in this PR and why they are needed:

• Summarize your change (mandatory)
• How does this PR work? Need a brief introduction for the changed logic (optional)
• Describe clearly one logical change and avoid lazy messages (optional)
• Describe any limitations of the current code (optional)

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)