build(deps): bump cachix/install-nix-action from V27 to 29 (#174)

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from V27 to 29. This release includes the previously tagged commit.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/cachix/install-nix-action/releases">cachix/install-nix-action's releases</a>.</em></p>
<blockquote>
<h2>v29</h2>
<p>Bumps Nix to 2.24.8 to fix CVE-2024-47174</p>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/cachix/install-nix-action/commit/9f70348d77d0422624097c4b7a75563948901306"><code>9f70348</code></a> Merge pull request <a href="https://redirect.github.com/cachix/install-nix-action/issues/215">#215</a> from Mic92/nix-bump</li>
<li><a href="https://github.com/cachix/install-nix-action/commit/4f91dc2b65dd81b86830c57b0d3bc75eb0502a25"><code>4f91dc2</code></a> Nix: 2.24.6 -&gt; 2.24.7</li>
<li><a href="https://github.com/cachix/install-nix-action/commit/3715ab1a11cac9e991980d7b4a28d80c7ebdd8f9"><code>3715ab1</code></a> bump channel</li>
<li><a href="https://github.com/cachix/install-nix-action/commit/1872f1ff9dba0f554710b1ed396fb6b2263ffdfd"><code>1872f1f</code></a> Nix: 2.22.1 -&gt; 2.24.6</li>
<li><a href="https://github.com/cachix/install-nix-action/commit/e268b7aa055cc66167f27239fc889bcd1b15683c"><code>e268b7a</code></a> Merge pull request <a href="https://redirect.github.com/cachix/install-nix-action/issues/213">#213</a> from phaer/patch-1</li>
<li><a href="https://github.com/cachix/install-nix-action/commit/5b8c65d4d79bb2d232054c72252fa78a29c36b8a"><code>5b8c65d</code></a> Update README: hardware accel is available now...</li>
<li><a href="https://github.com/cachix/install-nix-action/commit/ba01fffc512be2cf5d4dce85159f0e40621f84ec"><code>ba01fff</code></a> Merge pull request <a href="https://redirect.github.com/cachix/install-nix-action/issues/210">#210</a> from guoard/patch-1</li>
<li><a href="https://github.com/cachix/install-nix-action/commit/474f0a77aa820d33566f8f2035f8268d4023cc13"><code>474f0a7</code></a> docs(readme): update checkout action version</li>
<li><a href="https://github.com/cachix/install-nix-action/commit/725982224ce3b974b7abc7df9ca873679eda8939"><code>7259822</code></a> readme: V27</li>
<li>See full diff in <a href="https://github.com/cachix/install-nix-action/compare/V27...v29">compare view</a></li>
</ul>
</details>
<br />


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</details>

.github/workflows/ipxe.yaml

@@ -11,7 +11,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
       - name: Install nix
-        uses: cachix/install-nix-action@V27
+        uses: cachix/install-nix-action@v29
         with:
           nix_path: nixpkgs=channel:nixos-unstable
       - name: Build iPXE