rel: Prepare 2.5.1 release (#1147)

## Which problem is this PR solving?
Prepares the 2.5.1 release.

## Short description of the changes
- Add changelog entry
- Add release notes entry

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Refinery Changelog
 
+## 2.5.1 2024-05-15
+
+### Fixes
+
+- fix: Clarify what has-root-span does (#1114) | [Phillip Carter](https://github.com/cartermp)
+- fix: Add validation for ingest keys (#1066) | [Kent Quirk](https://github.com/kentquirk)
+- fix: Deal with locking issues at startup (#1060) | [Kent Quirk](https://github.com/kentquirk)
+- fix: Update cache lookup to use read lock (#1145) | [Joshua Jones](https://github.com/senojj)
+
+### Maintenance
+
+- maint: Bump protobuf (#1058) | [Kent Quirk](https://github.com/kentquirk)
+- maint(deps): bump the minor-patch group with 4 updates (#1073) | [dependabot[bot]](https://github.com/dependabot[bot])
+
 ## 2.5.0 2024-03-12
 
 The main feature is support of Honeycomb Classic ingest keys; there is also a performance improvement for the new

RELEASE_NOTES.md

@@ -2,6 +2,11 @@
 
 While [CHANGELOG.md](./CHANGELOG.md) contains detailed documentation and links to all the source code changes in a given release, this document is intended to be aimed at a more comprehensible version of the contents of the release from the point of view of users of Refinery.
 
+## Version 2.5.1
+
+This is a bug fix release for a concurrent map read panic when loading items from the internal cache.
+It also includes improvements for validation of ingest keys and resolves a lock issue during startup.
+
 ## Version 2.5
 
 This release's main new feature adds support of Honeycomb Classic ingest keys.