rm duplicated NSPhotoLibraryUsageDescription

README.md

 <string>Some description</string>
 <key>NSPhotoLibraryUsageDescription</key>
 <string>Some description</string>
-<key>NSPhotoLibraryUsageDescription</key>
-<string>Some description</string>
 <key>NSSpeechRecognitionUsageDescription</key>
 <string>Some description</string>