[AUTO] Add release notes for 3.7.0

[opensearch-ci-bot]

Add release notes for 3.7.0

Borderline Calls

• Add isIndexNotFoundException utility to AlertingException #934: Placed in Features — could be Enhancements since it adds a utility method to an existing class, but it introduces net new functionality (exception chain walking) needed for SDK migration.
• Hide metadata field from REST API responses using secure flag #948: Placed in Enhancements — could be Bug Fixes if the metadata exposure was considered a defect, but the PR describes it as an improvement following an existing pattern.
• Onboard code diff analyzer/reviewer and issue dedupe workflows (common-utils) #946: Placed in Enhancements — has the "enhancement" label. Could also be Infrastructure since it adds CI workflows.
• Cleanup SafeSerializationUtils to remove unused Guava classes #958: Placed in Maintenance — the PR itself categorizes it as Maintenance. Could be Refactoring since it removes unused code, but the security hardening aspect makes Maintenance more appropriate.
• fix: Change ScheduleJobPayload.jobStartTime from Instant to String #944: Placed in Bug Fixes — the "fix:" prefix in the subject and the nature of correcting a type choice that prevented proper functionality support this categorization, though it could be Enhancements.
• PPL Alerting: changing max PPL Monitor name length to 100 #962: Placed in Enhancements — it's a configuration change that improves usability rather than a new feature or bug fix.

[github-actions]

PR Reviewer Guide 🔍

(Review updated until commit 533141d)

Here are some key observations to aid the review process:

🧪 No relevant tests

🔒 No security concerns identified

✅ No TODO sections

🔀 No multiple PR themes

⚡ No major issues detected

[github-actions]

Persistent review updated to latest commit 533141d