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

[renovate[bot]]

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`](https://togithub.com/golang/go/compare/go1.21.5...go1.21.6) [Compare Source](https://togithub.com/golang/go/compare/go1.21.5...go1.21.6)

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Configuration

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• [ ] If you want to rebase/retry this PR, check this box

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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

Additional details and impacted files

```diff @@ 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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