ci: bump DeterminateSystems/nix-installer-action from 14 to 15 (#121)

Bumps [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action) from 14 to 15.
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](DeterminateSystems/nix-installer-action@v14...v15)

---
updated-dependencies:
- dependency-name: DeterminateSystems/nix-installer-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>

.github/workflows/ci.yaml

@@ -37,11 +37,11 @@ jobs:
 
       - name: Install Nix
         if: matrix.system != 'aarch64-linux'
-        uses: DeterminateSystems/nix-installer-action@v14
+        uses: DeterminateSystems/nix-installer-action@v15
 
       - name: Install Nix (with aarch64)
         if: matrix.system == 'aarch64-linux'
-        uses: DeterminateSystems/nix-installer-action@v14
+        uses: DeterminateSystems/nix-installer-action@v15
         with:
           extra-conf: "extra-platforms = aarch64-linux arm-linux"
 
@@ -78,7 +78,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v14
+        uses: DeterminateSystems/nix-installer-action@v15
 
       - name: Run check
         run: |

.github/workflows/publish.yaml

@@ -18,7 +18,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v14
+        uses: DeterminateSystems/nix-installer-action@v15
 
       - name: Push to Flakehub
         uses: DeterminateSystems/flakehub-push@v5

.github/workflows/update-flake.yaml

@@ -26,7 +26,7 @@ jobs:
           token: ${{ steps.app-token.outputs.token }}
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v14
+        uses: DeterminateSystems/nix-installer-action@v15
 
       - name: Run update
         run: nix flake update