Update golang Docker tag to v1.21.1

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
golang	final	minor	1.20.6 -> 1.21.1

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[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (f96e8e2) 66.05% compared to head (3735034) 66.05%.

❗ Current head 3735034 differs from pull request most recent head 06e7901. Consider uploading reports for the commit 06e7901 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #238   +/-   ##
=======================================
  Coverage   66.05%   66.05%           
=======================================
  Files           4        4           
  Lines         436      436           
=======================================
  Hits          288      288           
  Misses        140      140           
  Partials        8        8           

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