Update actions/checkout action to v2.4.0

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	minor	v2.3.5 -> v2.4.0

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Release Notes

actions/checkout

### [`v2.4.0`](https://togithub.com/actions/checkout/releases/v2.4.0) [Compare Source](https://togithub.com/actions/checkout/compare/v2.3.5...v2.4.0) - Convert SSH URLs like `org-@​github.com:` to `https://github.com/` - [pr](https://togithub.com/actions/checkout/pull/621)

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Configuration

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