v0.5.1 release changelog setting (#78)

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## Purpose of Changes and their Description
Changelog adjustment for release `v0.5.1`.

## Are these changes tested and documented?
N/A - changelog for release

- [ ] If tested, please describe how. If not, why tests are not needed.
- [ ] If documented, please describe where. If not, describe why docs
are not needed.
- [x] Added to `Unreleased` section of `CHANGELOG.md`?

CHANGELOG.md

@@ -45,6 +45,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+### Removed
+
+### Fixed
+
+### Security
+
+
+## v0.5.1
+
+### Added
+
 * [#75](https://github.com/allora-network/allora-offchain-node/pull/75) Configurable fee awareness
 
 ### Removed