Update change log for next release

CHANGELOG.md

@@ -5,6 +5,47 @@ 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).
 
+## [0.3.0] - Unreleased
+
+### Breaking changes
+
+The static and dynamic tensor types (`NdTensorBase`, `TensorBase`) have been
+unified into a single implementation. Most code uses these via type aliases
+(`NdTensor`, `Tensor` etc.), which remain the same. However there have been some
+API changes as a result:
+
+ - The `View` and `NdView` traits were combined into `AsView`. The recommended
+   way to import this trait is via the prelude (`use rten_tensor::prelude::*`)
+
+ - Some inherent methods of `TensorBase` moved to the `AsView` trait. You may
+   need to add additional imports of this trait or the prelude.
+
+ - `NdTensor::from_data` now has the same API signature as `Tensor::from_data`.
+   This means the order of arguments is reversed compared to before. It is now
+   `from_data(shape, data)`. Creating tensors with custom strides is now done
+   via `from_data_with_strides` or `from_slice_with_strides`.
+
+ - Tensor methods for broadcasting and reshaping tensors now determine the rank
+   of the result from the type of the shape argument. If passed an array, they
+   return a static-rank view. If passed a slice, they return a dynamic-rank
+   view.
+
+ - Methods that insert, remove or swap axes now have an `_axis` suffix (eg.
+   `move_axis`). Previously some of these methods had a `_dim` suffix.
+
+ - The `slice` method now always returns a static rank view. Usage is
+   `tensor.slice::<M, _>(range)` where `M` is the rank of the result. To create
+   a view with a dynamic dimension count, use `tensor.slice_dyn(range)` instead.
+
+## Other changes
+
+ - Optimized index iteration for tensors (d3fd3c9)
+ - Optimized col2im transform used by ConvTranspose (fbc541b)
+ - Optimized depthwise convolution (20e83e8)
+ - Improved performance on Arm via a better optimized GEMM kernel
+   ([#32](https://github.com/robertknight/rten/pull/32)) and vectorized kernels
+   for other functions ([#31](https://github.com/robertknight/rten/pull/31)).
+
 ## [0.2.0] - 2024-01-03
 
  - Improved inference performance on ARM [#30](https://github.com/robertknight/rten/pull/30)