chore(deps): update golang docker tag to v1.21.6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
golang	final	patch	1.21.5-alpine3.18 -> 1.21.6-alpine3.18
golang		patch	1.21.5 -> 1.21.6

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Release Notes

golang/go (golang)

v1.21.6

Compare Source

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (c009b65) 76.16% compared to head (7e36a6d) 76.16%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #184   +/-   ##
=======================================
  Coverage   76.16%   76.16%           
=======================================
  Files          24       24           
  Lines        1867     1867           
=======================================
  Hits         1422     1422           
  Misses        355      355           
  Partials       90       90           

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