chore(deps): update golang docker tag to v1.21.0

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
golang	final	minor	1.20.7-alpine3.17 -> 1.21.0-alpine3.17

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[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (5021cad) 78.14% compared to head (e890657) 78.14%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #106   +/-   ##
=======================================
  Coverage   78.14%   78.14%           
=======================================
  Files          10       10           
  Lines        1446     1446           
=======================================
  Hits         1130     1130           
  Misses        244      244           
  Partials       72       72           

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