feat(workflow): add Cloudflare cache purge after S3 deployment

Add cache purge step to clear Cloudflare cache when website is
deployed to S3. Uses CLOUDFLARE_ZONE_ID and CLOUDFLARE_API_TOKEN
secrets for API authentication.

Author: xnoto

.github/workflows/workflow.yml

@@ -42,3 +42,10 @@ jobs:
           AWS_SECRET_ACCESS_KEY: ${{ secrets.ONION_AWS_SECRET_ACCESS_KEY }}
           AWS_REGION: ${{ secrets.ONION_AWS_REGION }}
           SOURCE_DIR: 'onion.makeitwork.cloud/'
+
+      - name: Purge Cloudflare Cache
+        run: |
+          curl -X POST "https://api.cloudflare.com/client/v4/zones/${{ secrets.CLOUDFLARE_ZONE_ID }}/purge_cache" \
+            -H "Authorization: Bearer ${{ secrets.CLOUDFLARE_API_TOKEN }}" \
+            -H "Content-Type: application/json" \
+            --data '{"purge_everything":true}'