bump golang 1.21.8 on release-2.9.0

[MinerYang]

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Comprehensive Summary of your change

Issue being fixed

Fixes #(issue)

Please indicate you've done the following:

• Well Written Title and Summary of the PR
• Label the PR as needed. "release-note/ignore-for-release, release-note/new-feature, release-note/update, release-note/enhancement, release-note/community, release-note/breaking-change, release-note/docs, release-note/infra, release-note/deprecation"
• Accepted the DCO. Commits without the DCO will delay acceptance.
• Made sure tests are passing and test coverage is added if needed.
• Considered the docs impact and opened a new docs issue or PR with docs changes if needed in website repository.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.38%. Comparing base (8d9f7f5) to head (0eb3777).

Additional details and impacted files

@@                Coverage Diff                @@
##           release-2.9.0   #20196      +/-   ##
=================================================
- Coverage          67.42%   67.38%   -0.04%     
=================================================
  Files                993      993              
  Lines             108990   108990              
  Branches            2752     2752              
=================================================
- Hits               73487    73448      -39     
- Misses             31546    31583      +37     
- Partials            3957     3959       +2     

Flag	Coverage Δ
unittests	67.38% <ø> (-0.04%)	⬇️

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see 9 files with indirect coverage changes

[wy65701436]

lgtm