Doc: Change recommended command for updating Android SDK

Fixes: QTBUG-74637
Change-Id: I1d242938695773c879426289fd578f598bf2c625
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Reviewed-by: BogDan Vatra <bogdan@kdab.com>

doc/src/platforms/android.qdoc

@@ -175,7 +175,7 @@ by installing the latest \c build-tools, \c platform-tools, \c emulator, and \c
 packages:
 
 \badcode
-./android update sdk
+./bin/sdkmanager --update
 \endcode
 
 To install a specific package, use \c sdkmanager from