build(deps): bump DeterminateSystems/nix-installer-action from 6 to 8

Bumps [DeterminateSystems/nix-installer-action](https://github.com/determinatesystems/nix-installer-action) from 6 to 8.
- [Release notes](https://github.com/determinatesystems/nix-installer-action/releases)
- [Commits](DeterminateSystems/nix-installer-action@v6...v8)

---
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

@@ -27,7 +27,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v6
+        uses: DeterminateSystems/nix-installer-action@v8
 
       - name: Get list of packages to build
         id: matrix
@@ -54,7 +54,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v6
+        uses: DeterminateSystems/nix-installer-action@v8
 
       # cachix-action will take care of pushing everything to the binary cache.
       - name: Set up binary cache

.github/workflows/update-flake.yml

@@ -44,7 +44,7 @@ jobs:
           git config user.email 41898282+github-actions[bot]@users.noreply.github.com
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v6
+        uses: DeterminateSystems/nix-installer-action@v8
 
       # This will fail if the branch already exists; since pull requests created
       # by this workflow should be auto-merged, an existing branch either means

.github/workflows/update-packages.yml

@@ -35,7 +35,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v6
+        uses: DeterminateSystems/nix-installer-action@v8
 
       - name: Get list of packages to update
         id: matrix
@@ -76,7 +76,7 @@ jobs:
           git config user.email 41898282+github-actions[bot]@users.noreply.github.com
 
       - name: Install Nix
-        uses: DeterminateSystems/nix-installer-action@v6
+        uses: DeterminateSystems/nix-installer-action@v8
 
       # This will fail if the branch already exists; since pull requests created
       # by this workflow should be auto-merged, an existing branch either means