Mention android:taskAffinity activity property in Android example (#521)

* Update README.md & AndroidManifest.xml

README.md

@@ -329,6 +329,8 @@ Use your Dropbox APP Key in place of `dropboxKey` below.  You need to add the `A
 </manifest>
 ```
 
+Your activity starting the authorization flow should also configured with `android:launchMode="singleTask"`. Also, if that activity is configured with `android:taskAffinity`, then the `AuthActivity` should also configured with the same task affinity, such that authorization result can be passed back to your activity.
+
 🚨[There is a known issue regarding apps with `targetSdk=33` regarding app-to-app authentication when the Dropbox App is installed](https://github.com/dropbox/dropbox-sdk-java/pull/471) 🚨
 A fix is being worked on and will be released in an upcoming version of the Dropbox Mobile App.
 

examples/android/src/main/AndroidManifest.xml

@@ -31,6 +31,9 @@
             android:exported="true"
             android:configChanges="orientation|keyboard"
             android:launchMode="singleTask">
+            <!-- Your activity starting authorization flow should also configured with android:launchMode="singleTask".
+                 If that activity is configured with android:taskAffinity, this AuthActivity should also configured
+                 with the same android:taskAffinity so the auth result can be correctly passed back. -->
             <intent-filter>
                 <data android:scheme="db-${dropboxKey}" />
 
@@ -66,4 +69,4 @@
                 android:resource="@xml/provider_paths" />
         </provider>
     </application>
-</manifest>
+</manifest>