mention camera requirement in manifest

Author: westnordost

app/src/main/AndroidManifest.xml

@@ -9,6 +9,7 @@
     <uses-feature android:glEsVersion="0x00030001" android:required="true" />
 
     <uses-feature android:name="android.hardware.screen.portrait" />
+    <uses-feature android:name="android.hardware.camera" android:required="true" />
 
     <application
         android:allowBackup="true"