Update README and changelog for upcoming guc 0.3 release

Author: pablode

CHANGELOG.md

@@ -1,6 +1,25 @@
 
 # Changelog
 
+## Version 0.3 - 2023-07-26
+
+Added
+* Binaries for USD v23.08 with MaterialX 1.38.7
+* Metainfo that UsdGlTF plugin does not support writing
+* Support for [KHR_materials_emissive_strength](https://github.com/KhronosGroup/glTF/blob/d3382c30eca18312bd9cc0b36d6a9ae60e1f1bae/extensions/2.0/Khronos/KHR_materials_emissive_strength/README.md) extension
+* Support for [KHR_materials_iridescence](https://github.com/KhronosGroup/glTF/tree/d3382c30eca18312bd9cc0b36d6a9ae60e1f1bae/extensions/2.0/Khronos/KHR_materials_iridescence/README.md) extension
+* Support for [KHR_materials_variants](https://github.com/KhronosGroup/glTF/blob/d3382c30eca18312bd9cc0b36d6a9ae60e1f1bae/extensions/2.0/Khronos/KHR_materials_variants/README.md) extension
+* Support for [KHR_texture_transform](https://github.com/KhronosGroup/glTF/blob/d3382c30eca18312bd9cc0b36d6a9ae60e1f1bae/extensions/2.0/Khronos/KHR_texture_transform/README.md) extension
+* Warnings about unsupported optional extensions
+
+Changed
+* Disabled file glTF PBR implementation option on USD v23.08+ due to an internal crash
+* Renamed 'tangentSigns' primvar to 'bitangentSigns'
+* Updated [Ecosystem Limitations](docs/Ecosystem_Limitations.md) document with latest USD/MaterialX versions
+
+Fixed
+* Normalmap UsdUVTexture:scale[3] not matching USD complianceChecker
+
 ## Version 0.2 - 2023-01-09
 
 Added

README.md

@@ -23,7 +23,7 @@ All glTF features except animation and skinning are implemented and get continuo
 
 ### Build
 
-You need <a href="https://github.com/PixarAnimationStudios/OpenUSD/tree/v23.08">USD 22.11+</a> with MaterialX and OpenImageIO support enabled.
+You need USD v22.11+ (e.g. <a href="https://github.com/PixarAnimationStudios/OpenUSD/tree/v23.08">v23.08</a>) with MaterialX and OpenImageIO support enabled.
 
 Do a recursive clone of the repository and set up a build folder:
 ```
@@ -69,10 +69,9 @@ An example asset conversion is described in the [Structure Mapping](docs/Structu
 
 Name                                | Status&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
 ------------------------------------|----------
-KHR_draco_mesh_compression          | ❌ Not supported
 KHR_lights_punctual                 | ✅ Partial <sup>1</sup>
-KHR_materials_emissive_strength     | ✅ Complete
 KHR_materials_clearcoat             | ✅ Complete
+KHR_materials_emissive_strength     | ✅ Complete
 KHR_materials_ior                   | ✅ Complete
 KHR_materials_iridescence           | ✅ Complete
 KHR_materials_sheen                 | ✅ Complete
@@ -81,10 +80,7 @@ KHR_materials_transmission          | ✅ Complete
 KHR_materials_unlit                 | 🚧 Planned
 KHR_materials_variants              | ✅ Complete
 KHR_materials_volume                | ✅ Partial <sup>2</sup>
-KHR_mesh_quantization               | ❌ Not supported
-KHR_texture_basisu                  | ❌ Not supported
 KHR_texture_transform               | ✅ Complete
-KHR_xmp_json_ld                     | ❌ Not supported
 
 <sup>\[1\]</sup> Spotlight cone falloff is ignored.  
 <sup>\[2\]</sup> Thickness is <a href="https://github.com/AcademySoftwareFoundation/MaterialX/pull/861">not supported</a> by the MaterialX glTF PBR implementation.