poetry: update bleak to v0.12.1

This is a bug fix release. Also since bleak is getting more stable, it
should be safe to no longer require a strict version.

Author: dlech

CHANGELOG.md

@@ -4,6 +4,11 @@ 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/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Changed
+- Updated `bleak` dependency to v0.12.1.
+
 ## [1.0.0-alpha.11] - 2021-07-05
 
 ### Added