chore(deps): bump cachix/install-nix-action from 25 to 26

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 25 to 26.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](cachix/install-nix-action@v25...v26)

---
updated-dependencies:
- dependency-name: cachix/install-nix-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/docs.yml

@@ -20,7 +20,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: cachix/install-nix-action@v25
+      - uses: cachix/install-nix-action@v26
         with:
           nix_path: nixpkgs=channel:nixos-unstable
           github_access_token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/release.yml

@@ -38,7 +38,7 @@ jobs:
       - uses: anchore/sbom-action/download-syft@v0.15.8
       - uses: docker/setup-qemu-action@v3
       - uses: docker/setup-buildx-action@v3
-      - uses: cachix/install-nix-action@v25
+      - uses: cachix/install-nix-action@v26
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
       - run: task setup