Upgrade Horreum branch to 0.18

Author: lampajr

.github/workflows/gh-pages.yml

@@ -34,7 +34,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: 'Hyperfoil/Horreum'
-          ref: '0.17'
+          ref: '0.18'
       - name: Setup Pages
         id: pages
         uses: actions/configure-pages@v2