Update Actions dependencies

Author: rocka

.github/workflows/build.yml

@@ -3,6 +3,7 @@ on:
   push:
     branches:
       - master
+
 permissions:
   contents: read
   pages: write
@@ -12,20 +13,20 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2.4.0
-      - uses: cachix/install-nix-action@v15
+      - uses: actions/checkout@v3
+      - uses: cachix/install-nix-action@v18
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
 
       - name: Build and deploy
         run: nix develop --command mkdocs build --site-dir public
-      
+
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v1
         with:
           path: public
-        
+
   deploy:
     environment:
       name: github-pages