Update actions/checkout action to v3

[mend-for-github-com[bot]]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	major	v2 -> v3

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Release Notes

actions/checkout

### [`v3`](https://togithub.com/actions/checkout/compare/v2...v3) [Compare Source](https://togithub.com/actions/checkout/compare/v2...v3)

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Configuration

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