Include note about known issue with Perfetto v47.0 and above. (#391)

README.md

@@ -7,6 +7,10 @@
 [![Installer Packaging (CPack)](https://github.com/ROCm/omnitrace/actions/workflows/cpack.yml/badge.svg)](https://github.com/ROCm/omnitrace/actions/workflows/cpack.yml)
 [![Documentation](https://github.com/ROCm/omnitrace/actions/workflows/docs.yml/badge.svg)](https://github.com/ROCm/omnitrace/actions/workflows/docs.yml)
 
+> [!NOTE]
+> Perfetto validation is done with trace_processor v46.0, as there is a known issue with v47.0.
+If you are experiencing problems viewing your trace in the latest version of [Perfetto](http://ui.perfetto.dev), then try using [Perfetto UI v46.0](https://ui.perfetto.dev/v46.0-35b3d9845/#!/).
+
 ## Overview
 
 AMD Research is seeking to improve observability and performance analysis for software running on AMD heterogeneous systems.