Use latest version of secret instead of a specific one. (#2062)

Author: Tuseeq1

cloudbuild-publish.yaml

@@ -21,7 +21,7 @@ steps:
       gh release create $version --generate-notes
 availableSecrets:
   secretManager:
-  - versionName: projects/178487900909/secrets/npm-publish-token/versions/2
+  - versionName: projects/178487900909/secrets/npm-publish-token/versions/latest
     env: 'NPM_TOKEN'
 artifacts:
   npmPackages: