github: workflows: bump DeterminateSystems/nix-installer-action

Bumps [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action) from 15 to 16.
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](DeterminateSystems/nix-installer-action@v15...v16)

---
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/bundix_lock.yml

@@ -17,7 +17,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@v15
+      - uses: DeterminateSystems/nix-installer-action@v16
       - uses: DeterminateSystems/magic-nix-cache-action@v8
 
       - run: nix run .#bundix-lock

.github/workflows/nix_flake_check.yml

@@ -10,7 +10,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@v15
+      - uses: DeterminateSystems/nix-installer-action@v16
       - uses: DeterminateSystems/magic-nix-cache-action@v8
 
       - run: nix flake check

.github/workflows/nix_flake_update.yml

@@ -17,7 +17,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v4
-      - uses: DeterminateSystems/nix-installer-action@v15
+      - uses: DeterminateSystems/nix-installer-action@v16
       - uses: DeterminateSystems/magic-nix-cache-action@v8
 
       - uses: DeterminateSystems/update-flake-lock@v24