Added release note for OTel Changes

Releases issue - https://github.com/github/releases/issues/3398

data/release-notes/enterprise-server/3-10/0-rc1.yml

@@ -196,6 +196,17 @@ sections:
           To make GitHub inclusive to all developers, GitHub has improved color contrast of the default light and dark themes, making them accessible to all users. These changes were made to Primer, [GitHub's Design System](https://primer.style/). For more information, see [GitHub Accessibility](https://accessibility.github.com/).
 
   changes:
+    # https://github.com/github/releases/issues/3398
+    - |
+      Field names for some service logs on GitHub Enterprise Server have changed as part of GitHub's gradual migration to internal semantic conventions for [OpenTelemetry](https://opentelemetry.io/). Additional field names were changed in GitHub Enterprise Server 3.9. If any tooling or processes in your environment rely on specific field names within logs, or log entries in specific files, the following changes may affect you.
+
+      - `level` is now `SeverityText`.
+      - `log_message`, `msg`, or `message` is now `Body`.
+      - `now` is now `Timestamp`.
+      - Custom field names such as `gh.repo.id` or `graphql.operation.name` use semantic names.
+      - Log statements that the instance would previously write to `auth.log`, `ldap.log`, or `ldap-sync.log` now appear in containerized logs for `github-unicorn` if the statement originated from a web request, or in logs for `github-resqued` if the statement originated from a background job.
+
+      For a full list of mappings, download the [OpenTelemetry attribute mapping CSV for GitHub Enterprise Server 3.9](/assets/ghes-3.9-opentelemetry-attribute-mappings.csv) and the [OpenTelemetry attribute mapping CSV for GitHub Enterprise Server 3.10](/assets/ghes-3.10-opentelemetry-attribute-mappings.csv).
     # https://github.com/github/releases/issues/3134
     - |
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