Updated CHANGELOG.md

Author: wvbbreu

CHANGELOG.md

@@ -19,6 +19,7 @@ project adheres to [Semantic Versioning](http://semver.org/).
 - Added `cu::DeviceMemory::memset2D()` and `cu::Stream::memset2DAsync()`
 - Added `cufft::FFT1DR2C` and `cufft::FFT1DC2R`
 - Added `cu::Device::getOrdinal()`
+- Improved HIP documentation and building instructions in `README.md`
 
 ### Changed