Update changelog

Author: ryankurte

CHANGELOG.md

@@ -5,9 +5,17 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
-
 ## [Unreleased]
 
+### Added
+
+### Changed
+
+
+## [v1.0.0-alpha.2] - 2020-10-16
+
+*** This is (also) an alpha release with breaking changes (sorry) ***
+
 ### Added
 - 10-bit addressing mode for I2C traits.
 - `try_set_state` method for `OutputPin` using an input `PinState` value.
@@ -129,7 +137,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 Initial release
 
-[Unreleased]: https://github.com/rust-embedded/embedded-hal/compare/v1.0.0-alpha.1...HEAD
+[Unreleased]: https://github.com/rust-embedded/embedded-hal/compare/v1.0.0-alpha.2...HEAD
+[v1.0.0-alpha.2]: https://github.com/rust-embedded/embedded-hal/compare/v1.0.0-alpha.1...v1.0.0-alpha.2
 [v1.0.0-alpha.1]: https://github.com/rust-embedded/embedded-hal/compare/v0.2.3...v1.0.0-alpha.1
 [v0.2.3]: https://github.com/rust-embedded/embedded-hal/compare/v0.2.2...v0.2.3
 [v0.2.2]: https://github.com/rust-embedded/embedded-hal/compare/v0.2.1...v0.2.2