[release-1.29] Bump Go to v1.21.8

[twz123]

Description

https://groups.google.com/g/golang-announce/c/5pwGVUPoMbg/m/46oA5yPABQAJ
https://go.dev/doc/devel/release#go1.21.8
https://github.com/golang/go/issues?q=milestone%3AGo1.21.8+label%3ACherryPickApproved

Fixes CVE-2024-24783, CVE-2023-45290, CVE-2023-45289, CVE-2024-24785 and CVE-2024-24784.

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]

Backport failed for release-1.28, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin release-1.28
git worktree add -d .worktree/backport-4171-to-release-1.28 origin/release-1.28
cd .worktree/backport-4171-to-release-1.28
git switch --create backport-4171-to-release-1.28
git cherry-pick -x bc76f88815d4d1a9b105b7257f1ca5a121b47c46