Update gateway.yaml (#18392)

Added changelog for Category Filtering in Network Policy Builder.

Author: NuelEdeh

src/content/changelogs/gateway.yaml

@@ -5,6 +5,10 @@ productLink: "/cloudflare-one/policies/gateway/"
 productArea: Cloudflare One
 productAreaLink: /cloudflare-one/changelog/
 entries:
+  - publish_date: "2024-11-20"
+    title: Category Filtering in the Network Policy Builder
+    description: |- 
+      Gateway users can now create Network Policies with Content Categories and Security Risks traffic selectors. This update simplifies malicious traffic blocking and streamlines network monitoring for improved security management.
   - publish_date: "2024-10-17"
     title: Per-account Cloudflare root certificate
     description: |-