Add empty CHANGELOG

CHANGELOG.md

+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
+
+## [Unreleased]
+
+## [1.0.0] - 2023-08-13
+
+Initial Release
+
+
+[unreleased]: https://git.flow3r.garden/flow3r/flow3r-firmware/-/compare/v1.0.0...main
+[1.0.0]: https://git.flow3r.garden/flow3r/flow3r-firmware/-/tags/v1.0.0
+