Install rsync in deploy workflow

The runner image doesn't include rsync by default.

.forgejo/workflows/deploy.yml

@@ -24,6 +24,9 @@ jobs:
       - name: Build
         run: zola build
 
+      - name: Install rsync
+        run: apt-get update && apt-get install -y rsync
+
       - name: Deploy via rsync
         run: |
           mkdir -p ~/.ssh