Bump changelog for v6.22.3

[DrJosh9000]

v6.22.3 (2024-07-22)

Full Changelog

Changed

• Bump Agent to v3.75.1 and Scaler to v1.8.0 #1345 (@DrJosh9000)

[!NOTE] Depending on how you upgrade existing stacks, you may not automatically be upgraded to v1.8.0 of Buildkite Agent Scaler. A work around exists for this known issue.

Agent Changelog

## [v3.75.1](https://github.com/buildkite/agent/tree/v3.75.1) (2024-07-22) [Full Changelog](https://github.com/buildkite/agent/compare/v3.75.0...v3.75.1) ### Fixed - Fix downloaded artifact permissions [#2894](https://github.com/buildkite/agent/pull/2894) (@DrJosh9000)