build(deps): bump cachix/install-nix-action from 31.8.4 to 31.9.0

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 31.8.4 to 31.9.0.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Changelog](https://github.com/cachix/install-nix-action/blob/master/RELEASE.md)
- [Commits](https://github.com/cachix/install-nix-action/compare/v31.8.4...v31.9.0)

---
updated-dependencies:
- dependency-name: cachix/install-nix-action
  dependency-version: 31.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/build.yml

@@ -21,7 +21,7 @@ jobs:
     steps:
       - uses: actions/checkout@v6
       - name: "Install Nix"
-        uses: cachix/install-nix-action@v31.8.4
+        uses: cachix/install-nix-action@v31.9.0
 
       - name: Find packages missing in the cache
         id: get-packages

.github/workflows/nix.yml

@@ -21,7 +21,7 @@ jobs:
       - uses: actions/checkout@v6
 
       - name: "Install Nix"
-        uses: cachix/install-nix-action@v31.8.4
+        uses: cachix/install-nix-action@v31.9.0
 
       - uses: cachix/cachix-action@v16
         with:

.github/workflows/update-flake.yml

@@ -24,7 +24,7 @@ jobs:
           token: "${{ secrets.GH_TOKEN}}"
 
       - name: "Install Nix"
-        uses: cachix/install-nix-action@v31.8.4
+        uses: cachix/install-nix-action@v31.9.0
 
       - uses: cachix/cachix-action@v16
         with:

.github/workflows/update-pkgs.yml

@@ -24,7 +24,7 @@ jobs:
           token: "${{ secrets.GH_TOKEN}}"
 
       - name: "Install Nix"
-        uses: cachix/install-nix-action@v31.8.4
+        uses: cachix/install-nix-action@v31.9.0
 
       - uses: cachix/cachix-action@v16
         with: