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

Author: dgaliffiAMD

README.md

@@ -7,6 +7,10 @@
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+> [!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.