update changelog with PR number

Author: leehinman

packages/cisco_nexus/changelog.yml

@@ -3,7 +3,7 @@
  changes:
  - description: Update Title and Description.
  type: enhancement
- link: https://github.com/elastic/integrations/pull/XXXXXXXXXX
+ link: https://github.com/elastic/integrations/pull/1957
 - version: "0.2.2"
  changes:
  - description: Fixed a bug that prevents the package from working in 7.16.