Fixed a bug on OSX where images with SingleChannel PixelFormat were being created with an RGB colour space

modules/juce_graphics/native/juce_mac_CoreGraphicsContext.mm

@@ -478,7 +478,8 @@ void CoreGraphicsContext::drawImage (const Image& sourceImage, const AffineTrans
 {
     const int iw = sourceImage.getWidth();
     const int ih = sourceImage.getHeight();
-    CGImageRef image = CoreGraphicsImage::getCachedImageRef (sourceImage, rgbColourSpace);
+    CGImageRef image = CoreGraphicsImage::getCachedImageRef (sourceImage, sourceImage.getFormat() == Image::PixelFormat::SingleChannel ? greyColourSpace
+                                                                                                                                       : rgbColourSpace);
 
     CGContextSaveGState (context);
     CGContextSetAlpha (context, state->fillType.getOpacity());