Update cachix/install-nix-action digest to 5261181 (#1058)

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yml

@@ -170,7 +170,7 @@ jobs:
         if: github.ref_type == 'tag'
 
       - name: Install Nix
-        uses: cachix/install-nix-action@754537aaedb35f72ab11a60cc162c49ef3016495 # v31
+        uses: cachix/install-nix-action@526118121621777ccd86f79b04685a9319637641 # v31
         with:
           github_access_token: ${{ secrets.GITHUB_TOKEN }}
         if: github.ref_type == 'tag'