[release-1.30] Bump Alpine to 3.19.6

[twz123]

Description

https://alpinelinux.org/posts/Alpine-3.18.10-3.19.5-3.20.4-released.html
https://alpinelinux.org/posts/Alpine-3.18.11-3.19.6-3.20.5-3.21.2-released.html

Fixes CVE-2024-9143.

Also use Go Docker image based on Alpine 3.20. Upstream no longer supports Alpine 3.19. Any further Go version bumps will require a newer Alpine version.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

• Manual test
• Auto test added

Checklist

• My code follows the style guidelines of this project
• My commit messages are signed-off
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

[k0s-bot]

Successfully created backport PR for release-1.29:

• [Backport release-1.29] Bump Alpine to 3.19.6 #5575