Update readme.

Author: Archie3d

README.md

@@ -8,7 +8,7 @@ Includes VSTi plugin example.
 ![Screenshot 1](https://raw.githubusercontent.com/Archie3d/QVst/master/screenshots/vst3_host.png)
 
 # Building
-Configure with CMake. No external dependencies required (except Qt 5).
+Configure with CMake. No external dependencies required (except Qt 5). VST3 SDK is referenced as git submodule.
 
 Compilation tested with MS Windows (Visual Studio 2017), and Qt 5.9.1.