OPT: 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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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.15%. Comparing base (8f8f7db) to head (8939eda).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #167   +/-   ##
=======================================
  Coverage   92.15%   92.15%           
=======================================
  Files          35       35           
  Lines         816      816           
  Branches       62       62           
=======================================
  Hits          752      752           
  Misses         45       45           
  Partials       19       19           

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