Update cachix/install-nix-action action to v29

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
cachix/install-nix-action	action	major	v27 -> v29

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Release Notes

cachix/install-nix-action (cachix/install-nix-action)

### [`v29`](https://redirect.github.com/cachix/install-nix-action/releases/tag/v29) [Compare Source](https://redirect.github.com/cachix/install-nix-action/compare/v27...v29) Bumps Nix to 2.24.8 to fix CVE-2024-47174

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Configuration

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