ci: stop pinning NixOS version

Author: nbdd0121

.github/workflows/ci.yml

@@ -19,15 +19,15 @@ concurrency:
 jobs:
   checks:
     name: Quality Check
-    runs-on: nixos-24.05
+    runs-on: nixos
     steps:
       - name: checkout
         uses: actions/checkout@v4
         with:
           submodules: 'recursive'
 
       - name: Install Nix
-        uses: cachix/install-nix-action@v24
+        uses: cachix/install-nix-action@v30
 
       - name: Nix Format Check
         run: nix fmt -- . --check

.github/workflows/site.yml

@@ -27,10 +27,10 @@ jobs:
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
-    runs-on: nixos-24.05
+    runs-on: nixos
     steps:
       - name: Install Nix
-        uses: cachix/install-nix-action@v27
+        uses: cachix/install-nix-action@v30
         with:
           extra_nix_config: |
             substituters = https://nix-cache.lowrisc.org/public/ https://cache.nixos.org/