chore(deps): update actions/checkout action to v6

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	major	v4 -> v6

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Release Notes

actions/checkout (actions/checkout)

v6

Compare Source

v5

Compare Source

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Configuration

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[what-the-diff]

PR Summary

• Updated GitHub Actions Checkout Action Version
  The GitHub Actions Checkout Action, which is a part of our workflow, was upgraded from version 4 to 6 in several files. This will bring better functionality and new features that will help us streamline our operations. Following files have been updated:
  • .github/workflows/code-style.yml
  • .github/workflows/mutation-tests.yml
  • .github/workflows/prettier.yml
  • .github/workflows/release.yaml
  • .github/workflows/static-analysis.yml
  • .github/workflows/tests.yml