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

[renovate-sh-app]

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

• Persist creds to a separate file by @​ericsciple in #​2286
• Update README to include Node.js 24 support details and requirements by @​salmanmkc in #​2248

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