Bump actions versions

Author: Kuuuube

.github/workflows/nix.yml

@@ -8,12 +8,12 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
-    - uses: cachix/install-nix-action@v24
+    - uses: actions/checkout@v6
+    - uses: cachix/install-nix-action@v31
       with:
         extra_nix_config: |
           access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
-    - uses: cachix/cachix-action@v12
+    - uses: cachix/cachix-action@v15
       if: github.event_name == 'push'
       with:
         name: opentabletdriver