Add a better list with unimplemented interfaces

src/common/serialization/vst3/README.md

@@ -1,9 +1,15 @@
 # VST3 interfaces
 
-We currently support all VST 3.0.0 interfaces. See
+See
 [docs/vst3.md](https://github.com/robbert-vdh/yabridge/blob/master/docs/vst3.md)
 for more information on how the serialization works.
 
+The following interfaces are not yet implemented:
+
+- Every interface introduced after VST 3.0.0
+- The [Presonus extensions](https://presonussoftware.com/en_US/developer),
+  although most of these things seem to overlap with newer VST3 interfaces
+
 VST3 plugin interfaces are implemented as follows:
 
 | yabridge class             | Included in         | Interfaces                                             |