Bump cachix/install-nix-action from 25 to 26 (#669)

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@6004951...8887e59)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -171,7 +171,7 @@ jobs:
         if: github.ref_type == 'tag'
 
       - name: Install Nix
-        uses: cachix/install-nix-action@6004951b182f8860210c8d6f0d808ec5b1a33d28 # v25
+        uses: cachix/install-nix-action@8887e596b4ee1134dae06b98d573bd674693f47c # v26
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
         if: github.ref_type == 'tag'