Add changelog

Author: maxvp

src/content/changelogs/gateway.yaml

@@ -5,6 +5,10 @@ productLink: "/cloudflare-one/policies/gateway/"
 productArea: Cloudflare One
 productAreaLink: /cloudflare-one/changelog/
 entries:
+  - publish_date: "2024-10-10"
+    title: Time-based policy duration
+    description: |-
+      Gateway now offers [time-based DNS policy duration](/cloudflare-one/policies/gateway/dns-policies/timed-policies/#time-based-policy-duration). With policy duration, you can configure a duration of time for a policy to turn on or set an exact date and time to turn a policy off.
   - publish_date: "2024-10-04"
     title: Expanded Gateway log fields
     description: |-