Update CHANGELOG.md format

Author: jjcarstens

CHANGELOG.md

@@ -1,10 +1,17 @@
 # Changelog
 
-## v0.1.1
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-* Bug fixes
-  * Improve error return when the RTC isn't found
+## [v0.1.1] - 2020-03-15
 
-## v0.1.0
+### Fixed
+
+* Improve error return when the RTC isn't found
+
+## [v0.1.0] - 2020-03-15
 
 Initial release
+
+[v0.1.1]: https://github.com/nerves-time/nerves_time_rtc_abracon/releases/tag/v0.1.1
+[v0.1.0]: https://github.com/nerves-time/nerves_time_rtc_abracon/releases/tag/v0.1.0