Updated Readme to use auto Bundle Id replacement 
Updated Readme to use auto Bundle Id replacement 

This makes this more consistent with intune integration where $(PRODUCT_BUNDLE_IDENTIFIER) is used
 and simpler on the user as Bundle Id is auto replaced. This is also helpful for app that get resigned with a new Bundle ID
AzureAD/microsoft-authentication-library-for-objc,AzureAD/microsoft-authentication-library-for-objc,AzureAD/microsoft-authentication-library-for-objc,AzureAD/microsoft-authentication-library-for-objc,AzureAD/microsoft-authentication-library-for-objc