Updates 2.8 release notes#1460

DarshitChanpura merged 2 commits intoopensearch-project:2.8opensearch-project/security-dashboards-plugin:2.8from

DarshitChanpura:update-2.8-release-notesDarshitChanpura/security-dashboards-plugin:update-2.8-release-notesCopy head branch name to clipboard