Add secrets for Cache datastream and fix changelog PR entry

Author: devamanv

packages/couchbase/changelog.yml

@@ -2,7 +2,7 @@
   changes:
     - description: Add separate username and password configuration options, and enable secret for the password field.
       type: enhancement
-      link: https://github.com/elastic/integrations/pull/9869
+      link: https://github.com/elastic/integrations/pull/10490
 - version: "1.7.0"
   changes:
     - description: ECS version updated to 8.11.0. Update the kibana constraint to ^8.13.0. Modified the field definitions to remove ECS fields made redundant by the ecs@mappings component template.

packages/couchbase/data_stream/cache/agent/stream/stream.yml.hbs

@@ -7,6 +7,12 @@ period: {{period}}
 metrics_path: /metrics
 metrics_filters:
   include: ["sgw_cache*"]
+{{#if username}}
+username: {{username}}
+{{/if}}
+{{#if password}}
+password: {{password}}
+{{/if}}    
 {{#if ssl_sync_gateway}}
 ssl:
   {{ssl_sync_gateway}}