Update deploy.yml

.github/workflows/deploy.yml

@@ -26,6 +26,14 @@ jobs:
       - name: Build plugin(s)
         run: pnpm lune ci
 
+      - name: Copy additional files
+        run: |
+          cp README.md dist/README.md
+          printf -- "---\npermalink: /404.html\n---\n" > dist/404.md
+          printf -- "> **Note:** You accessed a link that returned a 404, probably by clicking one of the plugin links. You're supposed to copy the link address and add it into shelter.\n\n" >> dist/404.md
+          printf -- "remote_theme: pages-themes/cayman\n" > dist/_config.yml
+          cat README.md >> dist/404.md
+
         # Documentation: https://github.com/peaceiris/actions-gh-pages
       - name: Deploy to GitHub Pages
         uses: peaceiris/actions-gh-pages@v3