juce_RTAS_Wrapper.cpp fix

Hi Jules,

I had to fix line 512 in juce_RTAS_Wrapper.cpp today when building a plugin in XCode:
void handleAsyncUpdate() override
"Semantic Issue: Only virtual member functions can be marked ‘override’"
–> had to remove “override”


Ah, sorry - I automatically added “override” to all the uses of that method, but in that case it was just a name-clash. Thanks!