chore(deps): bump DeterminateSystems/nix-installer-action from 13 to 15

Bumps [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action) from 13 to 15.
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](https://github.com/determinatesystems/nix-installer-action/compare/v13...v15)

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

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

.github/workflows/build.yml

@@ -23,7 +23,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v13
+        uses: DeterminateSystems/nix-installer-action@v15
 
       - name: Build
         run: nix build -L --show-trace .#${{ matrix.path }}

.github/workflows/check-inputs.yml

@@ -13,7 +13,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v13
+        uses: DeterminateSystems/nix-installer-action@v15
 
       - name: Check Nix flake Nixpkgs inputs
         uses: DeterminateSystems/flake-checker-action@v9