defmt changelog and all-feature CI

Author: avlec

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ on:
 name: Continuous integration
 
 env:
-  RUSTFLAGS: '--deny warnings'
+  RUSTFLAGS: '--deny warnings --all-features'
 
 jobs:
   ci-linux:

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Added 
+
+- Support for optional package `defmt` which allows for easy conversion for
+error types when using tools like `probe-rs` for logging over debuggers.
+
 ## [v0.5.1] - 2023-07-26
 
 ### Added