Document #485 and MatrixAlgebraKit 0.6.9 bump in changelog

Author: lkdvos

docs/src/Changelog.md

@@ -44,6 +44,8 @@ When releasing a new version, move the "Unreleased" changes to a new version sec
 - Consolidated duplicated GPU logic into a new GPUArrays extension ([#460](https://github.com/QuantumKitHub/TensorKit.jl/pull/460))
 - Removed explicit dependence on cuTENSOR for the CUDA extension ([#455](https://github.com/QuantumKitHub/TensorKit.jl/pull/455))
 - Improved `DimensionMismatch` error message in the `TensorMap` constructor ([#456](https://github.com/QuantumKitHub/TensorKit.jl/pull/456))
+- Added docstrings for `catdomain` and `catcodomain` ([#485](https://github.com/QuantumKitHub/TensorKit.jl/pull/485))
+- Bumped minimum `MatrixAlgebraKit` to 0.6.9 ([#465](https://github.com/QuantumKitHub/TensorKit.jl/pull/465))
 
 ### Fixed