On IOS platform, iphone and simulator are different targets. To produce one framework for both targets, you need to use xcframwork. First, build each framework separately then run xcodebuild to combine multi frameworks into xcframework.

xcodebuild -create-xcframework -framework Release-iphoneos/VerovioFramework.framework -framework Release-iphonesimulator/VerovioFramework.framework  -output Verovio.xcframework