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

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	major	v5 -> v6

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Release Notes

actions/checkout (actions/checkout)

v6

Compare Source

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Configuration

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Slowest examples

Top 4 slowest examples (2.33 seconds, 99.99% of total time)

Example	Description	Time in seconds
spec/unit/recipes/windows_spec.rb:11	git::windows is expected to install git_client "default"	1.39417
spec/unit/recipes/default_spec.rb:12	git::default on windows is expected to install git_client "default"	0.78325
spec/unit/recipes/default_spec.rb:18	git::default on linux is expected to install git_client "default"	0.08494
spec/unit/recipes/source_spec.rb:14	git::source is expected to install_from_source git_client "default"	0.07302