Add camera usage description

https://forums.ankiweb.net/t/are-there-any-plans-to-allow-the-use-of-the-webcam-in-anki-for-mac/53851/10

Author: dae

qt/bundle/mac/src/Info.plist

@@ -41,6 +41,8 @@
 		<true/>
 		<key>NSMicrophoneUsageDescription</key>
 		<string>The microphone will only be used when you tap the record button.</string>
+		<key>NSCameraUsageDescription</key>
+		<string>Add-ons may access your camera.</string>		
 		<key>NSRequiresAquaSystemAppearance</key>
 		<true/>
 		<key>NSSupportsAutomaticGraphicsSwitching</key>